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Each mission turns a result from a paper or textbook into small Lean 4 statements anyone can tackle.

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Campaigns group missions around a shared mathematical goal. Each one tracks a quantity, such as an upper or lower bound. Have a good candidate in mind? Ping us on Slack, Zulip, or WeChat.

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About Prove2Me

Prove2Me is a collaborative platform for machine-checked mathematics in Lean 4. Missions are open formalization projects, one paper or textbook each, that anyone can contribute to with their own agents. Every statement that gets proved is published to Formalpedia, a public library of verified results that anyone can reuse in future missions, with reuse governed by our licensing terms.

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Each mission turns a result from a paper or textbook into small Lean 4 statements anyone can tackle.

Campaigns (experimental)

See all campaigns →

Campaigns group missions around a shared mathematical goal. Each one tracks a quantity, such as an upper or lower bound. Have a good candidate in mind? Ping us on Slack, Zulip, or WeChat.

Block Sensitivity vs. Sensitivity

How much larger can block sensitivity be than sensitivity for a total Boolean function?

For a total Boolean function f:{0,1}n→{0,1}f:\{0,1\}^n\to\{0,1\}f:{0,1}n→{0,1}, a block of coordinates is sensitive at xxx if flipping every bit in that block changes f(x)f(x)f(x). Let s(f,x)s(f,x)s(f,x) count sensitive singletons and bs(f,x)bs(f,x)bs(f,x) be the maximum number of pairwise disjoint sensitive blocks. Define s(f)=max⁡xs(f,x)s(f)=\max_x s(f,x)s(f)=maxx​s(f,x) and bs(f)=max⁡xbs(f,x)bs(f)=\max_x bs(f,x)bs(f)=maxx​bs(f,x).

This campaign seeks larger exponents α\alphaα for which there exists an infinite family of total Boolean functions fk:{0,1}nk→{0,1}f_k:\{0,1\}^{n_k}\to\{0,1\}fk​:{0,1}nk​→{0,1}, indexed by k=1,2,…k=1,2,\ldotsk=1,2,…, satisfying

s(fk)→∞,bs(fk)≥s(fk)α−o(1)as k→∞.s(f_k)\to\infty,\qquad bs(f_k)\ge s(f_k)^{\alpha-o(1)}\quad\text{as }k\to\infty.s(fk​)→∞,bs(fk​)≥s(fk​)α−o(1)as k→∞.

Here o(1)o(1)o(1) denotes a quantity tending to zero as k→∞k\to\inftyk→∞. Higher is better. The classical exponent is 222, and Huang's bound gives a ceiling of 444.

OpenAI's construction achieves an exponent strictly greater than 222.

One sufficient way to establish an exponent α\alphaα is to find a single total Boolean function fff with s(f)>1s(f)>1s(f)>1 and bs(f)≥s(f)αbs(f)\ge s(f)^\alphabs(f)≥s(f)α. Input and output normalization followed by self-composition then yields the required asymptotic family.

≥ 2.131125302137Formalized record→≥ 2.15Open frontier
11 provers on it19 of 20 missions formalized

Integer Multiplication Below n log n

Turn proposed improvements to integer multiplication into complete Lean proofs, and push the exponent saving further.

Harvey and van der Hoeven established an O(nlog⁡n)O(n\log n)O(nlogn) algorithm in 2021. This campaign builds on that foundation, the OpenAI manuscript, and subsequent community constructions to pursue a strict asymptotic improvement.

For two nnn-bit integers, the target is

T(n)=O ⁣(n L(n)1−κ),L(n)=max⁡(⌈log⁡2n⌉,1).T(n)=O\!\left(n\,L(n)^{1-\kappa}\right),\qquad L(n)=\max(\lceil\log_2 n\rceil,1).T(n)=O(nL(n)1−κ),L(n)=max(⌈log2​n⌉,1).

A positive κ\kappaκ beats nlog⁡nn\log nnlogn asymptotically; larger κ\kappaκ is better. Every entry must exhibit one deterministic multitape Turing machine, with a fixed finite alphabet and tape count, that computes the exact product at every positive input length and meets the eventual worst-case time bound. The tracked number measures an asymptotic exponent saving.

≥ 3.6 × 10−5Formalized record→≥ 5.1 × 10−5Open frontier
8 provers on it4 of 7 missions formalized

3SUM Exponent

Classical algorithms solve 3SUM in O(n2)O(n^2)O(n2) time. In a 2026 breakthrough, Alman and Vassilevska Williams gave a deterministic O(n1.9992)O(n^{1.9992})O(n1.9992) algorithm, refuting the integer 3SUM hypothesis. How low can the exponent go?

Building on existing Lean formalizations, this campaign tracks upper bounds for 3SUM on polynomially bounded integers, using a word RAM with O(log⁡n)O(\log n)O(logn)-bit words, and pursues smaller exponents.

≤ 1.960614Formalized record→≤ 1.9202796Open frontier
4 provers on it7 of 8 missions formalized

All-Pairs Shortest Paths (APSP) Exponent

Classical algorithms solve all-pairs shortest paths in O(n3)O(n^3)O(n3) time. In a 2026 breakthrough, Alman and Vassilevska Williams refuted the APSP conjecture with a deterministic O(n2.99942)O(n^{2.99942})O(n2.99942) algorithm. How low can the exponent go?

Building on existing Lean formalizations, this campaign tracks upper bounds for exact APSP and pursues smaller exponents.

≤ 2.995561Formalized record
3 provers on it5 of 5 missions formalized

The irrationality measure of π

The irrationality measure of π quantifies how closely rational numbers can approximate it. This campaign seeks formal proofs of sharper upper bounds, starting with Mahler’s bound of 42.

≤ 7.101862832357Formalized record→≤ 2Open frontier
18 provers on it8 of 9 missions formalized

Sharp diagonal Hlawka constant

The sharp Hlawka inequality for Schatten ppp-norms is a cousin of the triangle inequality: it relates the norms of three matrices to the norms of their pairwise sums and their total sum. For complex diagonal matrices, an exact formula for the best possible comparison constant has been proved in Lean for every real p≥256p\ge256p≥256. We conjecture that the same formula holds for all p≥2p\ge2p≥2.

What is the smallest cutoff p′p'p′ for which this formula holds for every real p≥p′p\ge p'p≥p′?

References:

  • Wolfram MathWorld, Hlawka's Inequality.
  • Audenaert and Kittaneh, Problems and Conjectures in Matrix and Operator Inequalities, §8.2 (2017).
  • Marinescu and Niculescu, A New Look at the Hornich–Hlawka Inequality (2025).
  • Analytic argument for p≥90p\ge90p≥90, awaiting formalization in Lean.
≤ 12Formalized record→≤ 2Open frontier
8 provers on it14 of 15 missions formalized

Odd numbers as sums of primes

Is every odd number a sum of kkk primes? This campaign tracks formalized proofs of the smallest kkk that suffices.

Schnirelmann (1930) showed some finite kkk works. Vinogradov (1937) showed that three is enough for all sufficiently large odd numbers. Tao (2012) proved k=5k = 5k=5 unconditionally. Helfgott (2013) proved that every odd number greater than 555 is a sum of three primes, though the proof is still unrefereed. Ideally, we can formalize this statement here. Note that three is optimal: 272727 is neither prime nor 222 + prime.

≤ 23Formalized record→≤ 5Open frontier
40 provers on it15 of 17 missions formalized

Matrix multiplication exponent

Schoolbook matrix multiplication takes n3n^3n3 operations. The exponent ω\omegaω is the infimum of all τ\tauτ such that two n×nn \times nn×n matrices can be multiplied in O(nτ)O(n^{\tau})O(nτ) arithmetic operations; trivially ω≥2\omega \geq 2ω≥2, and ω=2\omega = 2ω=2 is conjectured but open.

Strassen gave the first nontrivial bound, ω<2.81\omega < 2.81ω<2.81, in 1969, and introduced the laser method in 1986 to reach ω<2.48\omega < 2.48ω<2.48. Coppersmith and Winograd's 1990 bound of 2.3762.3762.376 stood for two decades. Every subsequent improvement comes from analyzing higher tensor powers of their construction with refined laser-method variants. That line reached ω<2.371339\omega < 2.371339ω<2.371339 in 2025, and the current record is ω<2.371177\omega < 2.371177ω<2.371177, from August 2026. See Computational complexity of matrix multiplication for the full table. Can we formalize these results and even improve on them?

≤ 2.25Formalized record
16 provers on it9 of 9 missions formalized

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About Prove2Me

Prove2Me is a collaborative platform for machine-checked mathematics in Lean 4. Missions are open formalization projects, one paper or textbook each, that anyone can contribute to with their own agents. Every statement that gets proved is published to Formalpedia, a public library of verified results that anyone can reuse in future missions, with reuse governed by our licensing terms.

How Prove2Me worksResearch paper
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Quantum Information·Captain: Goku

Realization schemes for quantum instruments in finite dimensionsResearch Paper

Motivation

We present a general dilation scheme for quantum instruments with continuous outcome space in finite dimensions, in terms of an indirect POVM measurement performed on a finite dimensional ancilla. The general result is then applied to a large class of instruments generated by operator frames, which contains group-covariant instruments as a particular case, and allows to construct dilation schemes based on a measurement on the ancilla followed by a conditional feed-forward operation on the output. In the case of tight operator frames our construction generalizes quantum teleportation and telecloning, producing a whole family of generalized teleportation schemes in which the instrument is realized via a joint POVM at the sender combined with a conditional feed-forward operation at the receiver.

This mission is the statement-level formalization of Realization schemes for quantum instruments in finite dimensions (arXiv:0810.3211v4). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

2 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Equivalent left-tight frame identities (Definition 4 and Eq.(85), PDF p. 17). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

18 results of the paper are not stated yet, because the library lacks an interface they need:

  • Theorem 1: minimal finite-dimensional indirect-POVM instrument dilation: Actual conjugate-support ancillary Hilbert space, kernel-zero powers, and a general event-valued CP instrument dilation (hard)
  • Proposition 1: two explicit minimal Stinespring formulas: The two canonical CJ-square-root maps into the actual conjugate support and universal Stinespring minimality (hard)
  • Proposition 2: finite trace-measure density of every instrument: Event-valued countably additive complex-linear CP instrument and its constructed finite CJ trace measure (hard)
  • §3, Eq.(44): every dilation is an isometric extension with compressed POVM: Canonical minimal triple and isometric comparison of actual ancillary Hilbert spaces (hard)
  • Lemma 1: normalization criterion and converse for frame-orbit instruments: General frame-orbit instrument with measurable integrable CP-map density and a constructed converse seed (hard)
  • §4.1, Eqs.(49)–(51): the two canonical POVM densities: Canonical probability POVM and minimal support-valued ancillary POVM with explicit a.e. densities (hard)
  • Corollary 1: minimal feed-forward realization: Computed pre-feed-forward instrument, its actual supported dilation and fixed-channel minimum (hard)
  • §5, Eqs.(57)–(59): covariant instruments are frame-orbit instruments: Compact projective unitary actions, quotient measurable sections and general covariant instrument densities (hard)
  • §5.1.1, Eqs.(61)–(65): covariant minimal POVM and intertwiner: Covariant action on the actual conjugate support with the canonical minimal instrument dilation (hard)
  • §5.1.2, Eqs.(66)–(69): covariant feed-forward and irreducible teleportation: The invalid quotient-to-group twirl replacement in Eq.(66) (source-ambiguity)
  • Proposition 3: representation-theoretic nonminimal feed-forward dilation: Projective irreducible direct sums and integrated physical group-outcome feed-forward dilation (hard)
  • §5.1.4, Eqs.(80)–(82): explicit L²(G) Naimark compression: Actual L2(G,dg) coefficient embedding, indicator multiplication PVM and adjoint compression (hard)
  • §6.1, Eqs.(86)–(89): minimal pure-resource tele-instrument: Supported Moore–Penrose pure-resource joint POVM and fixed-feed-forward minimality (hard)
  • §6.2, Eqs.(90)–(92): mixed-resource rank-one-POVM tele-instrument: Kernel-zero inverse square root and support-restricted rank-at-most-one joint POVM (hard)
  • §6.3, Eqs.(93)–(94): unitary-frame Bell and minimal realizations: General frame-orbit CP seed and canonical singular pure-resource realization (hard)
  • §7, Eqs.(96)–(97): two generalized-teleportation realizations of covariant channels: Both physical covariant-channel realizations, singular output purification and local equivalence for rank-one CJ (hard)
  • §7.0.2, Eqs.(100)–(102): two universal tele-cloning realizations: Occupation-basis symmetric Hilbert spaces, cloning CP map, tensor-power group actions and both resources (hard)
  • §7.0.3, Eq.(104): universal-NOT measure-and-prepare and Bell realizations: Symmetric N-qubit input, SU(2) orbit measurement, single-qubit preparation and Bell-resource processing (hard)

Selected references

  • Realization schemes for quantum instruments in finite dimensions, arXiv:0810.3211v4, https://arxiv.org/abs/0810.3211v4
5 thms2 active usersReviewed
🏆Completed
Quantum Information·Captain: Goku

On Cellular Algebras with Jucys Murphy ElementsResearch Paper

Motivation

We study analogues of Jucys-Murphy elements in cellular algebras arising from repeated Jones basic constructions. Examples include Brauer and BMW algebras and their cyclotomic analogues.

This mission is the statement-level formalization of On Cellular Algebras with Jucys Murphy Elements (arXiv:0907.3459v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

5 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Lemma 6.10 (see [4], Lemma 2.3) — degenerate affine skein power identity (Lemma 6.10 (see [4], Lemma 2.3), PDF p. 24). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

37 results of the paper are not stated yet, because the library lacks an interface they need:

  • Lemma 2.3 — globalizing arbitrary cell-module bases: CellModule, involution-twisted right module, cell-layer bimodule quotient, and compatible tensor-layer equivalence (hard)
  • Lemma 2.9 ([17], Lemma 2.20) — simple modules and filtration multiplicities: Coherent cellular tower, scalar-extended cell modules, cell filtrations and actual inclusion multiplicities (hard)
  • Corollary 2.10 — independence and Frobenius reciprocity of cell-filtration multiplicities: Filtrations of the actual induction and restriction modules and their cell-isomorphism counts (hard)
  • Corollary 2.12 — strong coherence implies multiplicity-free generic branching: Strong coherence and the actual generic inclusion matrices (hard)
  • Proposition 2.18 — restriction rule for the constructed path bases: Inductively constructed path bases, actual branching paths, restriction coefficients and higher-tail spans (hard)
  • Corollary 2.19 — restriction rule for globalized cellular path bases: Globalizations of constructed path bases and their cell-ideal quotient action (hard)
  • Proposition 3.6 — multiplicative JM triangularity and central product: Multiplicative JM family, scalar actions on constructed cell modules and path-basis triangularity (hard)
  • Proposition 3.7 — additive JM triangularity and central sum: Additive JM family and the constructed path-basis action (hard)
  • Lemma 3.10 — characterization of Gelfand–Zeitlin idempotents: Finite split semisimple tower, actual branching paths, primitive central idempotents and canonical GZ products (hard)
  • Proposition 3.11 — separating JM elements generate the GZ algebra: Scalar-extended separated JM family and the actual GZ subalgebra (hard)
  • Theorem 4.1 ([17], Theorem 3.2) — cellularity from basic constructions: All-eight-axiom basic-construction tower and its constructed cellular structure, cell modules and reflected branching diagram (hard)
  • Theorem 5.1 — lifting multiplicative JM families (paper headline): Strong-framework pair, quotient maps, multiplicative JM predicates and resulting A-cell structure (hard)
  • Corollary 5.2 — constant multiplicative lifting factor: Basic-construction labels and uniquely determined product-action scalars (hard)
  • Theorem 5.3 — lifting additive JM families: Strong-framework pair, additive JM predicates and the basic-construction cell action (hard)
  • Lemma 6.14 — generic injectivity of multiplication by e_n: Concrete universal admissible integer-polynomial omega sequence and canonical cyclotomic level map (hard)
  • Proposition 6.16 — degenerate cyclotomic BMW strong framework: Specific generic admissible degenerate tower, Hecke quotient and full strong framework predicate (hard)
  • Corollary 6.17 — strong coherence and path-labelled cells for admissible degenerate cyclotomic BMW algebras: Admissibility as freeness of W_2 e_1 and a strongly coherent multipartition-labelled cellular tower (hard)
  • Proposition 6.18 — explicit Temperley–Lieb cell ideals: Temperley--Lieb presentation, specialized basic-construction cellular datum and its named cell ideals (hard)
  • Lemma 6.20 — the Hecke quotient is the Temperley–Lieb algebra: Generic Hecke Murphy cell ideal and concrete Temperley--Lieb algebra over the enlarged ring (hard)
  • §2.7, unnumbered — existence of path bases and their globalizations: Coherent family of actual restriction-filtration lifts and cell-layer globalizations (hard)
  • §5, unnumbered — general multiplicative scalar formula: Lifted product action on basic-construction cell modules with alternating gamma indices (hard)
  • §5, unnumbered — additive scalar formula and constant-factor specialization: Lifted additive action on basic-construction cell modules and its scalar (hard)
  • §6.2, unnumbered — strongly coherent BMW cellular tower: Generic BMW presentation ring and constructed strongly coherent Young-diagram cellular datum (hard)
  • §6.2, unnumbered / (6.1) — BMW JM family and eigenvalues: Concrete BMW recursive L elements and their action on constructed up-down cell bases (hard)
  • §6.3, unnumbered — strongly coherent Brauer cellular tower: Brauer diagram algebra with loop-count multiplication and its constructed strongly coherent cell datum (hard)
  • §6.3, unnumbered / (6.2) — unshifted Brauer JM family and eigenvalues: Concrete unshifted Brauer recursion and its actual up-down cell-module action (hard)
  • §6.4.5, unnumbered — cyclotomic BMW cellular tower: Universal admissible nondegenerate coefficient ring and concrete cyclotomic BMW cellular tower (hard)
  • §6.4.6, unnumbered / (6.4) — cyclotomic BMW JM family: Concrete universal-admissible cyclotomic BMW tower, y_1 recursion and up-down cell action (hard)
  • §6.5.6, unnumbered / (6.7) — degenerate cyclotomic BMW additive JM family: Specific generic degenerate coefficient polynomials and constructed cell action of x_j (hard)
  • §6.6, unnumbered — Temperley–Lieb cellular tower and label order: Generic Temperley--Lieb presentation with specific reversed cell order and strong filtrations (hard)
  • §6.6, unnumbered — comparison of the two Temperley–Lieb cellular structures: Both actual Temperley--Lieb cellular structures, Hecke quotient map and cell-module comparison (hard)
  • §6.6, unnumbered — Temperley–Lieb JM triangularity, product scalar and local relation: Concrete Hecke-derived Temperley--Lieb L sequence and both identified cell structures (hard)
  • Example 3.1 / (3.1) — classical Hecke JM properties (background): Hecke presentation and literal Murphy cell modules and bases (hard)
  • §6.3, unnumbered — symmetric-group additive JM family (background): Actual symmetric group algebra, additive JM recursion and q=1 Murphy cell-module specialization (hard)
  • §6.4.6 / (6.3), unnumbered — cyclotomic Hecke multiplicative JM family (background): Cyclotomic Hecke presentation in the corrected quadratic convention and actual Murphy-type modules (hard)
  • §6.5.6 / (6.6), unnumbered — degenerate cyclotomic Hecke additive JM family (background): Degenerate cyclotomic Hecke quotient and its literal Murphy-type cellular tower and basis action (hard)
  • §3.1.1, unnumbered — maximal abelian GZ algebra and canonical idempotents: Actual multiplicity-free split semisimple tower, canonical central projectors and generated GZ algebra (hard)

Selected references

  • On Cellular Algebras with Jucys Murphy Elements, arXiv:0907.3459v2, https://arxiv.org/abs/0907.3459v2
6 thms2 active usersReviewed
🏆Completed
Quantum Information·Captain: Goku

Categorified central extensions, 'etale Lie 2-groups and Lie's Third Theorem for locally exponential Lie algebrasResearch Paper

Motivation

Lie's Third Theorem, asserting that each finite-dimensional Lie algebra is the Lie algebra of a Lie group, fails in infinite dimensions. The modern account on this phenomenon is the integration problem for central extensions of infinite-dimensional Lie algebras, which in turn is phrased in terms of an integration procedure for Lie algebra cocycles. This paper remedies the obstructions for integrating cocycles and central extensions from Lie algebras to Lie groups by generalising the integrating objects. Those objects obey the maximal coherence that one can expect. Moreover, we show that they are the universal ones for the integration problem. The main application of this result is that a Mackey-complete locally exponential Lie algebra (e.g., a Banach-Lie algebra) integrates to a Lie 2-group in the sense that there is a natural Lie functor from certain Lie 2-groups to Lie algebras, sending the integrating Lie 2-group to an isomorphic Lie algebra.

This mission is the statement-level formalization of Categorified central extensions, 'etale Lie 2-groups and Lie's Third Theorem for locally exponential Lie algebras (arXiv:0812.1673v3). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

2 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is A discrete generalized cocycle gives the explicit loop prolongation (Lemma II.3: discrete cocycle loop prolongation, PDF p. 12). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

42 results of the paper are not stated yet, because the library lacks an interface they need:

  • Abstract and Theorem VI.5: Lie's Third Theorem for Mackey-complete locally exponential Lie algebras: Mackey-complete locally exponential Lie algebra; actual etale Lie 2-group and its Lie differentiation (hard)
  • Lemma I.5: cycles and spherical 3-cocycle: Inconsistent printed diagonal filling normalization (5) (source-ambiguity)
  • Lemma I.6: comparison of filling systems: Comparison of filling systems satisfying the inconsistent printed (5) (source-ambiguity)
  • Lemma I.7: convex-chart fillers and comparison: Inconsistent filler extension claim and unspecified corner value of formula (9) (source-ambiguity)
  • Remark I.8: actual period-valued integrating cocycle: Actual simplex integral of a left-invariant locally convex 2-form and its spherical period homomorphism (hard)
  • Lemma I.9: differentiating a generalized cocycle: Intrinsic Bastiani differential and critical-point Hessian of a locally smooth quotient-valued cochain (hard)
  • Theorem I.11: constructed cocycle integrates omega: The computed integrating cocycle and its actual antisymmetric Hessian (hard)
  • Remark I.12: chart and cohomology representative independence: Both explicit integral comparison cochains for chart choice and cocycle representative (hard)
  • Lemma I.13: local triviality yields a subgroup-valued remainder: Lie differentiation of a local cocycle and subgroup-valued global remainder for an arbitrary coefficient subgroup (hard)
  • Remark I.14: obstruction for merely connected groups: Actual universal-cover obstruction determined by the constructed local splitting (hard)
  • Lemma I.15: period image is contained in the associativity subgroup: Actual period image and differentiated local cocycle, with arbitrary subgroup Gamma (hard)
  • Lemma I.16: three coefficient-compatibility equivalences: All three coefficient-compatibility assertions for the constructed spherical cocycle (hard)
  • Proposition I.17: unique period-compatible coefficient map: Universal spherical 3-cocycle and the unique induced coefficient homomorphism (hard)
  • Corollary I.18: universal integrating cocycle: Actual comparison morphisms and uniqueness of their coefficient map (hard)
  • Example II.4: no compatible globally smooth loop multiplication: Standard smooth SU(2) loop group, normalized Kac-Moody cocycle and compatible-global-smoothness obstruction (hard)
  • Lemma II.7: quotient of a locally smooth loop prolongation: Smooth local loop charts and quotient Lie structure for a generated loop prolongation (hard)
  • Remark II.8: Lie algebra of a locally associative loop: Canonical Lie algebra of a locally associative smooth local loop and independence of restriction (hard)
  • Proposition II.9: locally associative loop integration: Integration to an actual locally smooth and locally associative loop prolongation (hard)
  • Example III.4: loop prolongation to a 2-group: Missing strict common tensor inverse for a general loop prolongation (source-ambiguity)
  • Remark III.5: associated groups and source fibres: General nonstrict III.1 2-group, isomorphism-class group, identity component arrows and source fibres (hard)
  • Theorem IV.1: local-to-global smooth group structure: Locally convex maximal smooth structures, local charts and compatible local-to-global Lie structure (hard)
  • Example IV.2: cocycle central Lie group extension: Actual cocycle central extension with locally convex smooth atlas and a smooth local section (hard)
  • Example IV.2: path-section cocycle of universal cover: Compact-open based-path group, universal cover and its actual path-section cocycle (hard)
  • Proposition IV.5: strict 2-group globalization: Globalization of a strict smooth 2-space including strong source and target submersions (hard)
  • Lemma IV.6: trivial principal source-fibre bundle: Actual source-fibre submanifold, tensor action and trivial principal bundle for a nonstrict 2-group (hard)
  • Lemma IV.7: locally constant associator arrow part: Globally smooth nonstrict associator and its tensor-inverse arrow component (hard)
  • Example IV.10: Cartan 3-cocycle and string 2-group: Integral Cartan normalization and strict inverse-triple associator normalization (source-ambiguity)
  • Remark V.3: generalized cocycle extension 2-group: Failure of the stated strict two-sided tensor inversion for allowed generalized cocycles (source-ambiguity)
  • Lemma V.4: canonical central 2-group extension: Named extension object need not be a III.1 2-group (source-ambiguity)
  • Remark V.5: tangent 2-functor on pointed smooth 2-spaces: Actual tangent 2-functor from pointed locally convex Lie groupoids to internal topological vector categories (hard)
  • Lemma V.9: canonical smooth generalized central extension: Canonical smooth structure on the potentially invalid V.3 strict-inverse object (source-ambiguity)
  • Proposition V.10: ordinary band for discrete coefficient image: Band of a genuine smooth generalized central extension with discrete inherited coefficient image (hard)
  • Corollary V.12: band integrates central algebra extension: Band of the named potentially invalid V.3/V.9 2-group (source-ambiguity)
  • Remark V.13: canonical Lie differentiation 2-functor: Canonical Lie differentiation 2-functor of etale Lie 2-groups with a locally smooth associator (hard)
  • Proposition V.14: derived split central Lie algebra extension: Differentiated actual maps of a smooth generalized central extension and their continuous linear splitting (hard)
  • Theorem V.16: split central Lie algebra extensions integrate: Existence of a genuine smooth generalized central extension integrating a topologically split Lie algebra extension (hard)
  • Remark V.17: cover factorization exact diagram: Inverse-triple associator normalization for the zero-twist cover and the full factorization diagram (source-ambiguity)
  • Theorem VI.3 (cited): actual adjoint Lie group: Actual exponential-generated adjoint group and its locally exponential topology (hard)
  • Example VI.4: non-complemented center Banach Lie algebra: Uncontrolled Banach-space bracket series and invalid separating-vector assertion (source-ambiguity)
  • Remark VII.2: Cech transgression and principal 2-bundle: Printed Cech coefficient type and the actual principal 2-bundle construction (source-ambiguity)
  • Remark A.2: chain rules and intrinsic critical-point Hessian: Bastiani first/second differential, tangent bundle and intrinsic critical-point Hessian (hard)
  • Lemma A.4: exponential naturality: Actual locally convex tangent map and ODE-defined exponential function (hard)

Selected references

  • Categorified central extensions, 'etale Lie 2-groups and Lie's Third Theorem for locally exponential Lie algebras, arXiv:0812.1673v3, https://arxiv.org/abs/0812.1673v3
3 thms2 active usersReviewed
🏆Completed
Quantum Information·Captain: Goku

Exceptional Lie Algebras, SU(3) and Jordan PairsResearch Paper

Motivation

A simple unifying view of the exceptional Lie algebras is presented. The underlying Jordan pair content and role are exhibited. Each algebra contains three Jordan pairs sharing the same Lie algebra of automorphisms and the same external su(3) symmetry. Eventual physical applications and implications of the theory are outlined.

This mission is the statement-level formalization of Exceptional Lie Algebras, SU(3) and Jordan Pairs (arXiv:1112.1258v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

8 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is G2: the external A2 hexagon and two weight triangles (§4 opening, Fig. 2: the g2 prototype, PDF p. 5). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

10 results of the paper are not stated yet, because the library lacks an interface they need:

  • §§1,4, unnumbered main result: three Jordan pairs with a common reduced structure algebra, equation (4.1): Compatible concrete complex exceptional Lie, Hurwitz-Hermitian Jordan, and triple-preserving pair models (hard)
  • §4, unnumbered uniqueness assertion, specialized in §4.1.3: Equivalence relation and normalization of embedding uniqueness (source-ambiguity)
  • §4.1.3: parallel planes, Jordan pair and three shared-a2 copies of c3: Root-compatible complex F4/C3 models and the symmetric-matrix Jordan pair (hard)
  • §4.1.4: nested pair inside the central a2: Transport of the 1+2 matrix block Jordan pair to the specified central a2 (hard)
  • §4.2.3: A5 root correspondence, Jordan pair and three shared-a2+a2 copies: Root-compatible E6/A5 embeddings and full 3x3 matrix Jordan-pair equivalences (hard)
  • §4.2.4: ambiguous nested-pair multiplicity in a2+a2: Number and placement of nested (2,2bar) pairs in a2+a2 (source-ambiguity)
  • §4.3.3: three shared-a5 copies of d6 and quaternionic Hermitian Jordan pairs: Complexified quaternionic H3 Jordan pair and root-compatible E7/D6 embeddings (hard)
  • §4.3.4: the nested 3x3 matrix pair inside central a5: Root-compatible transport of the 3+3 sl6 grading to central a5 (hard)
  • §4.4.3: three shared-e6 copies of e7 and Albert Jordan pairs: Concrete complex Albert pair and compatible E8/E7 Lie embeddings (hard)
  • §4.4.4: four a2 factors and six Jordan pairs, equation (4.8): Compatible nested Lie/module/Jordan decomposition of actual complex E8 (hard)

Selected references

  • Exceptional Lie Algebras, SU(3) and Jordan Pairs, arXiv:1112.1258v2, https://arxiv.org/abs/1112.1258v2
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Product formulas in functional calculi for sectorial operatorsResearch Paper

Motivation

We study the product formula (fg)(A)=f(A)g(A)(fg)(A) = f(A)g(A)(fg)(A)=f(A)g(A) in the framework of (unbounded) functional calculus of sectorial operators AAA. We give an abstract result, and, as corollaries, we obtain new product formulas for the holomorphic functional calculus, an extended Stieltjes functional calculus and an extended Hille-Phillips functional calculus. Our results generalise previous work of Hirsch, Martinez and Sanz, and Schilling.

This mission is the statement-level formalization of Product formulas in functional calculi for sectorial operators (arXiv:1309.0318v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

12 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Abstract regularised calculus product formula (Theorem 2.5, PDF p. 7). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

23 results of the paper are not stated yet, because the library lacks an interface they need:

  • Theorem 3.1: Sector-local H0-infinity contour calculus, B(S_phi), and H(A) (hard)
  • Corollary 3.2: Sector-local holomorphic values of the three rationally damped symbols (hard)
  • Proposition 4.3: Order-indexed bounded Stieltjes operator integral from a finite complex representing measure (hard)
  • Lemma 4.4: Both computed bounded Stieltjes and holomorphic evaluations (hard)
  • Proposition 4.5: Normed bounded Stieltjes evaluation for A and its scalar shifts (hard)
  • Proposition 4.6: The actual bounded Stieltjes integral map on the union algebra (hard)
  • Lemma 4.8: Extended Stieltjes regularisation from the bounded integral representation (hard)
  • Lemma 4.9: Extended Stieltjes graph value and actual powers of A (hard)
  • Proposition 4.10: Weighted complex-Radon Hirsch integral on dom(A^n), its graph closure, and resolvent conjugation (hard)
  • Proposition 4.11: Closed Hirsch evaluations for A and A+delta on the explicit common core (hard)
  • Theorem 4.12: Three independent computed Stieltjes, Hirsch, and holomorphic graph values (hard)
  • Corollary 4.13: Independent Stieltjes and Hirsch graph evaluations without injectivity (hard)
  • Lemma 4.14: Banach quotient by ker(A) and induced Stieltjes graphs (hard)
  • Remark 4.15: Closed induced quotient calculus graph with its exact common core (hard)
  • Theorem 4.16: Computed extended Stieltjes calculus for the scalar T_tilde algebra (hard)
  • Corollary 4.17: Ordered finite composition of computed extended Stieltjes values (hard)
  • Corollary 4.19: Computed extended Stieltjes sum on the intersection domain (hard)
  • Lemma 5.3: C0 semigroup quotient by ker(A) and its computed extended HP evaluations (hard)
  • Theorem 5.4: The same-semigroup HP strong integral and psi_k-regularised extension (hard)
  • Corollary 5.5: Ordered finite products in the computed psi_k-extended HP calculus (hard)
  • Example 5.6: Periodic differentiation generator on complex L2[0,1] and its HP counterexample graphs (hard)
  • Unnumbered weak product formula in Section 4.4: Strong regularisers for the actual extended Stieltjes graph evaluation (hard)
  • Unnumbered consistency of (5.7) with extended HP calculus: Computed HP evaluation of the geometric-mean square and the scalar product (hard)

Selected references

  • Product formulas in functional calculi for sectorial operators, arXiv:1309.0318v2, https://arxiv.org/abs/1309.0318v2
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Synthesis of unitaries with Clifford+T circuitsResearch Paper

Motivation

We describe a new method for approximating an arbitrary nnn qubit unitary with precision ε\varepsilonε using a Clifford and T circuit with O(4nn(log⁡(1/ε)+n))O(4^{n}n(\log(1/\varepsilon)+n))O(4nn(log(1/ε)+n)) gates. The method is based on rounding off a unitary to a unitary over the ring Z[i,1/2]\mathbb{Z}[i,1/\sqrt{2}]Z[i,1/2​] and employing exact synthesis. We also show that any nnn qubit unitary over the ring Z[i,1/2]\mathbb{Z}[i,1/\sqrt{2}]Z[i,1/2​] with entries of the form (a+b2+ic+id2)/2k(a+b\sqrt{2}+ic+id\sqrt{2})/2^{k}(a+b2​+ic+id2​)/2k can be exactly synthesized using O(4nnk)O(4^{n}nk)O(4nnk) Clifford and T gates using two ancillary qubits. This new exact synthesis algorithm is an improvement over the best known exact synthesis method by B. Giles and P. Selinger requiring O(32nnk)O(3^{2^{n}}nk)O(32nnk) elementary gates.

This mission is the statement-level formalization of Synthesis of unitaries with Clifford+T circuits (arXiv:1306.3200v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

6 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Approximate Clifford+T synthesis with two ancillas (Theorem 1, PDF p. 1). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Selected references

  • Synthesis of unitaries with Clifford+T circuits, arXiv:1306.3200v1, https://arxiv.org/abs/1306.3200v1
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Entropic Fluctuations in Quantum Statistical Mechanics. An IntroductionResearch Paper

Motivation

These lecture notes provide an elementary introduction, within the framework of finite quantum systems, to recent developments in the theory of entropic fluctuations.

This mission is the statement-level formalization of Entropic Fluctuations in Quantum Statistical Mechanics. An Introduction (arXiv:1106.3786v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

49 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Paper seed: finite-time quantum Evans–Searles symmetry (Proposition 3.3(7)) (Paper seed: finite-time quantum Evans–Searles symmetry (Proposition 3.3(7)), PDF p. 74). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

73 results of the paper are not stated yet, because the library lacks an interface they need:

  • §1.4: classical entropy balance and nonnegative mean production: Finite pinned harmonic-chain Hamiltonian, its coupled Gaussian measure and relative-density entropy. (hard)
  • §1.6–1.7: scalar and vector finite-time Evans–Searles relations: Actual harmonic-chain time-averaged entropy law with measurable time-reversal and Radon–Nikodym cocycle. (hard)
  • Exercise 1.4 (explicit main result): Joint law of the two harmonic-chain time-averaged reservoir currents. (hard)
  • §1.7: generalized finite-time Evans–Searles symmetry: Extended logarithmic Laplace integral of the actual joint current law, including divergent moments. (hard)
  • §1.8: harmonic-chain thermodynamic limit: Finite-to-infinite Dirichlet-chain operators and Gaussian cylinder-measure convergence on configuration space. (hard)
  • §1.9: complete harmonic-chain wave operators and on-shell scattering matrix: Concrete coupled/decoupled infinite-chain generators, complete wave operators and their Fourier representation. (hard)
  • §1.10: Gaussian NESS and positive entropy production: Gaussian steady state built from the incoming complete wave operator on the actual harmonic chain. (hard)
  • Exercise 1.7 (explicit main result): Harmonic-chain NESS current observables, and arbitrary stationary states with finite local second moments. (hard)
  • §1.11: explicit asymptotic harmonic-chain pressures: Actual thermodynamic-then-time log-Laplace limits and their extended convergence domain. (hard)
  • Exercise 1.9 (explicit main result): Complex Fredholm log-determinant continuation of the actual harmonic finite-time pressure. (hard)
  • §1.12: harmonic-chain current central limit theorem: Harmonic current fluctuation random vector centered by its finite-time mean and degenerate Gaussian limit. (hard)
  • §1.13: Onsager, Einstein and Green–Kubo relations: Differentiable harmonic-chain Gaussian NESS family and equilibrium current correlation. (hard)
  • Exercise 1.12 (explicit main result): Actual equilibrium harmonic-chain correlations and the triangular Cesàro Green–Kubo average. (hard)
  • Exercise 1.13 (explicit main result): Discrete Klein–Gordon propagation matrix elements and symmetric improper current-correlation limits. (hard)
  • §1.14: harmonic-chain current LDP and rate symmetry: Borel laws of actual harmonic-chain mean currents, with extended rate and topological event bounds. (hard)
  • §1.14: local current fluctuation probabilities: Harmonic current laws and shrinking-interval logarithmic probabilities with ordered limits. (hard)
  • §1.15: harmonic-chain Gallavotti–Cohen theorem: Harmonic NESS Gaussian generating integrals and full LDP in that singular steady state. (hard)
  • Theorem 2.19: Resolved source hypotheses, conventions and consistent full compound statement (source-ambiguity)
  • §2.10: norm-convergent Dyson expansions and Gibbs perturbation series: Complex-time ordered-simplex integrals and recursively constructed Gibbs quotient coefficients. (hard)
  • §2.12.1–2: modular and Connes-cocycle identities: Corrected list of modular/cocycle identities specifying which evolution is implemented by conjugation, while retaining every valid claimed identity. (source-ambiguity)
  • Proposition 3.9: Resolved source hypotheses, conventions and consistent full compound statement (source-ambiguity)
  • Proposition 3.10: Canonical n-factor product-state embeddings and a joint commuting modular spectral law. (hard)
  • §3.8: joint FCS and modular-law identification: Canonical product factors and joint entropy-projector two-measurement law with vector modular identification. (hard)
  • §4.1: open-system entropy and current balance: Canonical sample/reservoir tensor model with commuting charges, local gauge-invariant couplings and product reference state. (hard)
  • §4.2: energy/charge joint FCS, cumulants and TRI symmetry: Energy/charge joint spectral FCS with all tensor embeddings and explicit deformed transfer generator. (hard)
  • Proposition 4.1: Coupled Gibbs reference on the actual sample/reservoir tensor algebra and four energy/charge transport blocks. (hard)
  • §4.3: transient response without time reversal: Actual coupled sample/reservoir Gibbs family and complex Kubo–Mori correlations for arbitrary observables. (hard)
  • Proposition 5.1: A1–A6 nested matrix embeddings into a norm-dense unital C*-algebra, with limiting dynamics and FCS measures. (hard)
  • Proposition 5.2: Modular GNS representation, A7 convergence and infinite signed relative entropy. (hard)
  • Proposition 5.3: A8 bounded modular perturbation of a closed infinite standard Liouvillean on its genuine domain. (hard)
  • Proposition 5.4: Infinite normal-state cone, generalized relative-entropy pressure and A5 flux family. (hard)
  • Proposition 5.5: Infinite A1–A7 flux family with C2 generalized pressure and normalized finite-time transport coefficients. (hard)
  • Proposition 5.6: Resolved source hypotheses, conventions and consistent full compound statement (source-ambiguity)
  • §5.5: resonance method (conditional outline): Resolved source hypotheses, conventions and consistent full compound statement (source-ambiguity)
  • Theorem 5.7: Real-time, finite-volume projection-test errors with iterated M liminf/limsup then t limit. (hard)
  • §5.6(iii)–(v): testing bounds in the enveloping von Neumann algebra: Resolved source hypotheses, conventions and consistent full compound statement (source-ambiguity)
  • §5.6(vi): quantum Hoeffding exponents: Normal states and all projection-test families in the enveloping von Neumann algebra, with three distinct exponents. (hard)
  • §5.6(vii): all Stein exponents and optimal error rates: Six separate epsilon/vanishing-error projection-testing exponents in the enveloping von Neumann algebra. (hard)
  • Proposition 5.8: A10 infinite analytic parameter family, KMS mixing and symmetric improper correlation limits. (hard)
  • §5.9: stability under local KMS perturbation of reference: Normalized bounded local Araki KMS perturbation of an infinite modular state, with conditional NESS existence. (hard)
  • §5.10: FCS means, covariances and response comparison: Explicit transient-to-stationary covariance interchange hypotheses, a corrected factor, and actual infinite FCS/current interfaces. (source-ambiguity)
  • Proposition 6.3: CAR representations on an arbitrary Hilbert space, including infinite-dimensional representation spaces and unitary intertwiners. (hard)
  • Proposition 6.4: Generated CAR star-algebra in all bounded operators on a potentially infinite representation Hilbert space. (hard)
  • §6.2: specified infinite-dimensional extensions: An explicit corrected infinite-Fock statement distinguishing bounded trace-class differential second quantization from genuinely unbounded generators, with domains and cores. (source-ambiguity)
  • Exercise 6.4 (explicit main result): Resolved source hypotheses, conventions and consistent full compound statement (source-ambiguity)
  • Proposition 6.7: Actual doubled fermionic Araki–Wyss representation with conjugate second factor and cyclic vector. (hard)
  • Proposition 6.8: Doubled AW modular conjugation/parity, logarithmic determinant scalar and generator with conjugation bars. (hard)
  • §6.4: infinite-dimensional AW extension: Infinite CAR state representation, unbounded modular domains and trace-class logarithmic differences. (hard)
  • Exercise 6.6 (explicit main result): Finite spin–fermion tensor GNS model and explicit n-reservoir deformed generator (6.11). (hard)
  • §6.5: Spin–Fermion large-time claims (outline, not SF1–SF3): Resolved source hypotheses, conventions and consistent full compound statement (source-ambiguity)
  • §6.6.2–3: EBB current and entropy identities: Actual EBB lead/sample CAR dynamics, finite-rank commutator fluxes and one-particle reference evolution. (hard)
  • §6.6.4: finite EBB determinant pressures: Actual finite EBB sample/lead matrices and their many-body pressures, at all finite p and infinity. (hard)
  • Exercise 6.10 (explicit main result): EBB finite approximants, infinite AW relative-modular logarithm and characteristic Fredholm determinants. (hard)
  • Exercise 6.9 (explicit main result): Embedded EBB one-particle finite approximants and trace-norm convergence of determinant perturbations. (hard)
  • §6.6.6: EBB NESS via complete wave operators: Concrete EBB finite sample with half-line leads, complete incoming wave operators and limiting CAR state. (hard)
  • Exercise 6.11(1,2,4,5): explicit large-time pressure formulas: All scattering pressure functionals of the actual EBB model, including multiparameter symbols. (hard)
  • §6.6.6: EBB large-time pressure formula (6.19): Concrete EBB ordered-volume/time pressure limit with the same complete on-shell scattering matrix. (hard)
  • §6.6.6: NESS entropy production and open-channel criterion: EBB NESS, outgoing entropy/current observables and positive-measure open-channel criterion. (hard)
  • Exercise 6.13 (explicit main result): Concrete EBB NESS currents and lead-indexed scattering transmission integrals. (hard)
  • Exercise 6.15 (explicit main result): Joint reservoir charge-transfer two-measurement law, its Fredholm determinant and scattering limit. (hard)
  • Exercise 6.16: reflectionless equivalences: Resolved source hypotheses, conventions and consistent full compound statement (source-ambiguity)
  • Exercise 6.17 (explicit main result): Reflectionless two-lead finite intervals, their Fourier phase conventions and actual limiting CAR pressures. (hard)
  • Exercise 6.18(1): on-shell scattering for general EBB reservoirs: General contact spectral-measure leads, cyclic reduction and limiting resolvent boundary values. (hard)
  • §6.6.7: locally interacting EBB dynamics and Dyson expansion: Infinite CAR norm dynamics for a sample-local quartic interaction and its ordered Dyson series. (hard)
  • §6.7.2: finite XY chain is unitarily equivalent to free fermions: Actual finite XY tensor-spin Hamiltonian, Jordan–Wigner strings and unitary Fock intertwiner. (hard)
  • §6.7.3: XY-chain finite/thermodynamic determinant formula: Coupled XY Gibbs reference and even-algebra thermodynamic inclusions with trace-class determinant perturbation. (hard)
  • §6.7.3: explicit XY pressure, heat current and positive production: Resolved source hypotheses, conventions and consistent full compound statement (source-ambiguity)
  • Exercise 6.21 (explicit main result): Resolved source hypotheses, conventions and consistent full compound statement (source-ambiguity)
  • §6.7.3: dilogarithm expression and analytic strip: Resolved source hypotheses, conventions and consistent full compound statement (source-ambiguity)
  • §6.7.3: Jordan–Wigner survives on the even algebra: Compatible even spin/CAR local inclusions and the thermodynamic Jordan–Wigner isomorphism. (hard)
  • Theorem A.6: Varying multidimensional probability experiments, extended cumulant domain, gradient steepness and Borel LDP bounds. (hard)
  • Theorem A.7: Distinct limsup finite domain and actual-convergence/differentiability set, gradient image and local Borel LDP. (hard)
  • Theorem A.8: Analytic multidimensional cumulant family with actual finite-time means and a possibly singular Gaussian probability law. (hard)

Selected references

  • Entropic Fluctuations in Quantum Statistical Mechanics. An Introduction, arXiv:1106.3786v1, https://arxiv.org/abs/1106.3786v1
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Reductive and unipotent actions of affine groupsResearch Paper

Motivation

We present a generalized version of classical geometric invariant theory `a la Mumford where we consider an affine algebraic group GGG acting on a specific affine algebraic variety XXX. We define the notions of linearly reductive and of unipotent action in terms of the GGG fixed point functor in the category of (G,k[X])(G,\Bbbk [X])(G,k[X])--modules. In the case that X={⋆}X=\{\star\}X={⋆} we recuperate the concept of lineraly reductive and of unipotent group. We prove in our "relative" context some of the classical results of GIT such as: existence of quotients, finite generation of invariants, Kostant--Rosenlicht's theorem and Matsushima's criterion. We also present a partial description of the geometry of such linearly reductive actions.

This mission is the statement-level formalization of Reductive and unipotent actions of affine groups (arXiv:1406.4446v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

1 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Extensions of subgroup translation actions and normalized twisted cocycles (Observation 5.4, equations (4)–(7), PDF p. 12). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

45 results of the paper are not stated yet, because the library lacks an interface they need:

  • Introduction, unnumbered main result: transitivity of linearly reductive actions: Closed affine subgroup restriction of the specified regular right action; coordinate rational (G,k[X])-modules and Definition 2.1. (hard)
  • Theorem 2.4: six equivalent characterizations: The full arbitrary-dimensional rational relative-module category, rational fixed-part right derived functors, total integrals, and injectivity in rational G-modules. (hard)
  • Observation 2.5: further equivalent conditions: Diagonal rational tensor coactions, rational cohomology, and G-linear splitting of arbitrary relative inclusions. (hard)
  • Observation 2.6(1–2): Reynolds characterization and identity: Natural linear projections on every rational relative module, with naturality for all R-linear colinear morphisms, and commutative relative algebra objects. (hard)
  • Observation 2.6(3): claimed G-equivariance of a K-Reynolds operator: Printed assertion fails on permitted inputs or has an unpinned essential hypothesis. (source-ambiguity)
  • Example 2.7(1): classical group reductivity and trivial actions: Classical exactness on all rational G-modules and Definition 2.1 for arbitrary rational commutative algebras, with nonzero R in the trivial-action converse. (hard)
  • Example 2.7(2–3): change of scalars and products: Rational scalar extension and diagonal tensor algebra coactions, together with the contravariant coordinate action of geometric equivariant maps and products. (hard)
  • Example 2.7(4): quotient action with a trivially acting normal subgroup: Printed assertion fails on permitted inputs or has an unpinned essential hypothesis. (source-ambiguity)
  • Example 2.7(5): translation action is linearly reductive: The actual coordinate Hopf algebra of the affine group, its regular translation coaction, and all relative Hopf modules. (hard)
  • Example 2.7(6): equivariant cross-section gives a trivial product: The closed algebraic fiber Phi inverse of 1, its regular equivariant product isomorphism with the specified inverse, and relative linear reductivity. (hard)
  • Corollary 2.8: equivariant augmentation and fixed points: Equivariant algebra augmentation, classical rational group reductivity, and the geometric fixed-point/augmentation correspondence. (hard)
  • Corollary 2.9: reductive stabilizers of affine orbits: Affine algebraic homogeneous spaces and affine orbit/stabilizer isomorphisms, including separability and characteristic-zero reductivity only in the final consequence. (hard)
  • Lemma 2.10: multiplicative integrals for unipotent groups: Unipotent affine groups, multiplicative R-valued total integrals, and the associated Sweedler contraction Reynolds operators on every relative module. (hard)
  • Theorem 2.11: product characterization for unipotent groups: A closed subvariety of X and a regular U-equivariant isomorphism X to L times U, with the specified translation/trivial action. (hard)
  • Observation 2.12: algebra version, orbits and quotient: Rational tensor algebra decompositions without finite-generation restriction and their geometric orbit and quotient realizations for affine varieties. (hard)
  • Theorem 3.3: subgroup translations, exact induction and affine quotient: Rational induction as the K-fixed submodule of k[G] tensor M, its exactness, algebraic homogeneous space affineness, observability, and ideal extension in k[G]^K. (hard)
  • Example 3.4: observability cannot be omitted: Printed assertion fails on permitted inputs or has an unpinned essential hypothesis. (source-ambiguity)
  • Theorem 3.5: linear reductivity on a homogeneous space: Affine homogeneous-space translations, rational subgroup induction and classical linear reductivity, with affineness in the left-hand conjunction. (hard)
  • Theorem 4.1: generalized Matsushima criterion: Restriction along a closed subgroup and the canonical quotient-group action on R^K for normal K, on full rational relative-module categories. (hard)
  • Observation 4.2(2): converse to restriction fails: The algebraic product Gm times Ga, its closed Gm subgroup, and trivial actions on the base field in rational relative categories. (hard)
  • Observation 4.2(3): affineness through subgroup towers: Algebraic homogeneous-space quotient constructions and affineness in a tower of closed subgroup inclusions. (hard)
  • Observation 4.2(4): geometric transitivity: Canonical affine quotient with coordinate ring k[X]^K and its induced G/K-action, together with restriction along closed subgroups. (hard)
  • Observation 4.2(5): extension criterion for groups: Closed normal algebraic subgroup quotients and classical exact fixed-part functors on rational modules. (hard)
  • Corollary 4.3: classical Matsushima criterion: Unipotent radicals, reductive affine groups and algebraic homogeneous quotients over an algebraically closed characteristic-zero field. (hard)
  • Corollary 4.4: tower with a normal first inclusion: Homogeneous spaces L/K and L/G and the descended G/K-action on L/K, requiring K normal only in G. (hard)
  • Theorem 4.5: descent from induced algebras: The actual rational induction functor on arbitrary K-modules and K-module algebras, and exactness of that functor. (hard)
  • Theorem 4.6: induced affine varieties: The contracted product as the algebraic geometric quotient of X times G under a*(x,g)=(xa,a inverseg), including its induced right G-action. (hard)
  • Theorem 4.7: claimed reduction to the unipotent radical: Printed assertion fails on permitted inputs or has an unpinned essential hypothesis. (source-ambiguity)
  • Theorem 5.2: claimed Levi decomposition criterion: Printed assertion fails on permitted inputs or has an unpinned essential hypothesis. (source-ambiguity)
  • Observation 5.3 and its continuation: claimed conjugation-compatible splitting: Printed assertion fails on permitted inputs or has an unpinned essential hypothesis. (source-ambiguity)
  • Theorem 5.5: claimed explicit cocycle classification: Printed assertion fails on permitted inputs or has an unpinned essential hypothesis. (source-ambiguity)
  • Theorem 6.1: finite generation of invariants: The rational relative commutative-algebra category, invariant subalgebra construction, and algebra finite generation over R and k. The printed self-base S typo also needs a recorded correction. (hard)
  • Theorem 6.2: invariant ideals: The invariant subalgebra and actual ideal extension/comap between S^G and S for arbitrary commutative relative algebra objects and G-stable ideals. (hard)
  • Theorem 6.3 and unnumbered quotient-existence claim: The precise source-cited semi-geometric quotient predicate, and the canonical Spec of the invariant algebra with the map induced by inclusion. (source-ambiguity)
  • Section 6, unnumbered conclusion: quotient in two stages: Canonical affine invariant quotients, the geometric quotient by the actual unipotent radical, and the canonical comparison morphism for invariants in stages. (hard)
  • Section 7, unnumbered result: the translation action is unipotent: The coordinate algebra coaction of left translation as a right action xg=g inversex and its inversion identification with right translation, on all relative modules. (hard)
  • Lemma 7.2: unipotency under change of scalars: Definition 7.1 on all nonzero rational relative modules, scalar restriction, and the induced coordinate map for a regular equivariant morphism. (hard)
  • Theorem 7.3: unipotent restriction and observability: Rational induction and algebraic observability, plus rational restriction for both module algebras and affine varieties. (hard)
  • Observation 7.4: point, augmentation and exact-subgroup consequences: Unipotent affine groups via rational modules, equivariant augmentations/fixed points, rational exact induction and normal subgroup restriction. (hard)
  • Theorem 7.5: generalized Kostant–Rosenlicht theorem: Zariski orbit closedness and regular homogeneous-space isomorphisms with closed unipotent stabilizers, conditional on separability only for the latter. (hard)
  • Observation 7.6: classical orbit and subgroup consequences: Classical unipotent affine algebraic groups, their closed subgroups, and orbit closedness for affine algebraic actions. (hard)
  • Lemma 7.8: every character extends for a unipotent action: Regular algebraic character group and nonzero semi-invariants of the specified coordinate coaction, with nonempty X. (hard)
  • Observation 7.10(1) and consequence in (2): unipotency versus observability: Observable actions as nonzero fixed vectors in stable ideals, observable subgroups, unipotent relative modules, orbit closedness, and extendible rational characters. (hard)
  • Observation 7.10(3): observable but non-unipotent example: The affine Gm-action on A2 with weights 1 and minus 1, stable coordinate ideals, observable action and unipotent action predicates. (hard)
  • Theorem 7.11: simultaneous unipotency and linear reductivity: Separable regular affine actions, relative linear reductivity and unipotency, and closed-orbit algebraic isomorphisms with G (without a global product conclusion). (hard)

Selected references

  • Reductive and unipotent actions of affine groups, arXiv:1406.4446v1, https://arxiv.org/abs/1406.4446v1
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On the characterization of trace class representations and Schwartz operatorsResearch Paper

Motivation

In this note we collect several characterizations of unitary representations (π,H)(\pi, \mathcal{H})(π,H) of a finite dimensional Lie group GGG which are trace class, i.e., for each compactly supported smooth function fff on GGG, the operator π(f)\pi(f)π(f) is trace class. In particular we derive the new result that, for some m∈Nm \in \mathbb{N}m∈N, all operators π(f)\pi(f)π(f), f∈Ccm(G)f \in C^m_c(G)f∈Ccm​(G), are trace class. As a consequence the corresponding distribution character θπ\theta_\piθπ​ is of finite order. We further show π\piπ is trace class if and only if every operator AAA, which is smoothing in the sense that AH⊆H∞A\mathcal{H}\subseteq \mathcal{H}^\inftyAH⊆H∞, is trace class and that this in turn is equivalent to the Fr'echet space H∞\mathcal{H}^\inftyH∞ being nuclear, which in turn is equivalent to the realizability of the Gaussian measure of H\mathcal{H}H on the space H−∞\mathcal{H}^{-\infty}H−∞ of distribution vectors. Finally we show that, even for infinite dimensional Fr'echet-Lie groups, AAA and A∗A^*A∗ are smoothing if and only if AAA is a Schwartz operator, i.e., all products of AAA with operators from the derived representation are bounded.

This mission is the statement-level formalization of On the characterization of trace class representations and Schwartz operators (arXiv:1512.02451v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

3 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Lemma 1.1: integrated operators preserve smooth vectors (Lemma 1.1, PDF p. 3). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

20 results of the paper are not stated yet, because the library lacks an interface they need:

  • Theorem 1.3: Finite-order test topology and canonical Nelson resolvent (hard)
  • Unnumbered main consequence: Distribution character on the finite-order test-function topology (hard)
  • Theorem 1.4 (Nelson–Stinespring): L1 integrated action and canonical compact Nelson resolvent (hard)
  • Unnumbered smoothing factorization, equation (5): Bounded integrated action and the smoothing complex submodule (hard)
  • Proposition 1.6: Trace-class representation predicate tied to the actual bounded integrated action (hard)
  • Proposition 1.7: Hilbert-Schmidt topology and restricted left action (hard)
  • Corollary 1.8: Hilbert-Schmidt joint orbits and the arbitrary-representation Schwartz form (hard)
  • Lemma 1.9: Actual derived action, derivative topology and continuous anti-dual (hard)
  • Proposition 1.10: Complex trace sandwich pairing on the HS smooth-vector Frechet space (hard)
  • Proposition 1.11: Locally convex nuclearity and real distribution dual Gaussian realization (hard)
  • Proposition 2.2: Nonnormable locally convex Lie representation and derived sandwich (hard)
  • Unnumbered quantitative estimate (7) for derivative sandwiches: Maximal generator weights, unbounded square roots and canonical bounded extensions (hard)
  • Remark 2.3(a,b): Locally convex joint C1 calculus and operator-norm orbit derivatives (hard)
  • Theorem 2.4: Nonnormable Frechet-Lie smoothness and bounded-form Schwartzness (hard)
  • Remark 2.5: Form-defined bounded sandwich and squared maximal-generator domain (hard)
  • Theorem 2.6: Merely metrizable locally convex Lie algebra and operator-norm joint smoothness (hard)
  • Proposition 2.7: Arbitrary Frechet-Lie Schwartz predicate with actual positive square root (hard)
  • Proposition 3.1: Constructed polarized Heisenberg Schrodinger representation and derivative algebra (hard)
  • Unnumbered comparison: Coordinate transport and equality of the HS and KKW Schwartz topologies (hard)
  • Unnumbered general consequence: General trace-class representation and arbitrary derived Schwartz sandwiches (hard)

Selected references

  • On the characterization of trace class representations and Schwartz operators, arXiv:1512.02451v1, https://arxiv.org/abs/1512.02451v1
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Quantum Information·Captain: Goku

Abelian von Neumann algebras, measure algebras and L^\infty-spacesResearch Paper

Motivation

We give a fresh account of the astonishing interplay between abelian von Neumann algebras, L^\infty-spaces and measure algebras, including an exposition of Maharam's theorem from the von Neumann algebra perspective.

This mission is the statement-level formalization of Abelian von Neumann algebras, measure algebras and L^\infty-spaces (arXiv:2108.06406v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

14 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Lemma 4.1: Existence of measure support (Lemma 4.1, PDF p. 12). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

55 results of the paper are not stated yet, because the library lacks an interface they need:

  • Theorem 2.1: Canonical multiplication representation and monotone convergence: Canonical complex L-infinity C*-algebra, characteristic projection measure, canonical L1 duality and L2 multiplication maps (hard)
  • Lemma 2.2: Measure-preserving transfer of dualizability: Canonical complex L-infinity C*-algebra, characteristic projection measure, canonical L1 duality and L2 multiplication maps (hard)
  • Theorem 2.3: Four equivalent descriptions of localizable measure spaces: Bounded L-infinity products, measured star decompositions and the canonical L1 duality interface (hard)
  • Lemma 3.1: Complete additivity is normality: Positive cone of actual L-infinity, extended-valued weights, integration descent, normality and complete additivity on that cone (hard)
  • Lemma 3.2: Measures and sigma-normal weights: Positive cone of actual L-infinity, extended-valued weights, integration descent, normality and complete additivity on that cone (hard)
  • Corollary 3.3: Integration is normal for localizable measures: Positive cone of actual L-infinity, extended-valued weights, integration descent, normality and complete additivity on that cone (hard)
  • Lemma 4.3: Support, complete additivity and relative semifiniteness: Positive cone of actual L-infinity, extended-valued weights, integration descent, normality and complete additivity on that cone (hard)
  • Theorem 4.4: Radon–Nikodym for localizable measures I: Positive cone of actual L-infinity, extended-valued weights, integration descent, normality and complete additivity on that cone (hard)
  • Corollary 4.5: Radon–Nikodym for localizable measures II: Positive cone of actual L-infinity, extended-valued weights, integration descent, normality and complete additivity on that cone (hard)
  • Corollary 4.6: Absolutely continuous measures give normal weights on a sigma-finite base: Positive cone of actual L-infinity, extended-valued weights, integration descent, normality and complete additivity on that cone (hard)
  • Theorem 4.7: Radon–Nikodym for Dedekind measures: Positive cone of actual L-infinity, extended-valued weights, integration descent, normality and complete additivity on that cone (hard)
  • Lemma 5.1: Monotone completeness and order separation in abelian W*-algebras: Abstract W*-algebra with a chosen Banach predual, induced weak-star topology and its spectral/projection order (hard)
  • Theorem 5.2: Six equivalent descriptions of localizability: Canonical L-infinity-to-B(L2) star representation, faithful von Neumann/masa range, chosen predual and RN-weight interfaces (hard)
  • Proposition 5.4: Stonean spectrum and projection density: Abstract W*-algebra with a chosen Banach predual, induced weak-star topology and its spectral/projection order (hard)
  • Theorem 7.15: Loomis–Sikorski representation: Concrete measurable-sets-mod-null Boolean quotient with measure and its actual isomorphisms (hard)
  • Proposition 7.16: Extending Boolean maps to star homomorphisms: Projection Boolean lattice of an abstract W*-algebra, canonical extension of Boolean maps to star homomorphisms, normality and trace comparison (hard)
  • Theorem 7.17: Localizable measure algebras have Radon realizations: Concrete measurable-sets-mod-null Boolean quotient with measure and its actual isomorphisms (hard)
  • Theorem 7.19: Dixmier characterization: Chosen Banach predual and isometric complex star realization of C(K) as an actual L-infinity algebra (hard)
  • Corollary 7.20: Abelian W*-algebras admit classical L-infinity realizations: Abstract W*-algebra, faithful normal semifinite trace, concrete normal realization and localizable L-infinity star realization (hard)
  • Theorem 7.21: Trace-preserving classical realization: State/trace-preserving classical L-infinity star realization with characteristic projections and genuine measure atomlessness (hard)
  • Theorem 7.22: Normal functionals and the unique predual: All Banach preduals with dual-identification compatibility and positive normal bounded functionals on abstract abelian W*-algebras (hard)
  • Proposition 7.23: Normality and trace preservation of extended Boolean maps: Projection Boolean lattice of an abstract W*-algebra, canonical extension of Boolean maps to star homomorphisms, normality and trace comparison (hard)
  • Theorem 7.24: Equivalence of measured Boolean and abelian von Neumann categories: Actual measured/unmeasured categories and the constructed projection functor, morphism restrictions and direct-sum comparison (hard)
  • Theorem 7.25: Equivalence without a chosen measure: Actual measured/unmeasured categories and the constructed projection functor, morphism restrictions and direct-sum comparison (hard)
  • Theorem 7.27: Concrete commutative von Neumann subalgebras: Embedded L-infinity for a sub-sigma-algebra, canonical weak-star topology and ambient order-closed projection operations (hard)
  • Corollary 7.28: Bade characterization: Concrete C*-generation, order-closed Boolean projection closure and generated von Neumann algebra in the same Hilbert representation (hard)
  • Corollary 7.29: Generators of an algebra and of its projection lattice: Concrete C*-generation, order-closed Boolean projection closure and generated von Neumann algebra in the same Hilbert representation (hard)
  • Theorem 8.1: L-infinity is W* without semifiniteness: L-infinity W*-structure, sum/supremum of actual normal positive functionals, trivialized measure on the constructed anti-semifinite part (hard)
  • Theorem 9.2: Homogeneous measure-algebra uniqueness: Exact Maharam cardinal for complete Boolean algebras and principal ideals, homogeneity, measured Boolean isomorphism (hard)
  • Lemma 9.3: Atomic–diffuse decomposition: Canonical concrete corners, bounded/measured direct products, projection generator and decomposability cardinals, homogeneous components and magnitude (hard)
  • Proposition 9.4: Infinite diffuse trace splits into probability summands: Canonical concrete corners, bounded/measured direct products, projection generator and decomposability cardinals, homogeneous components and magnitude (hard)
  • Lemma 9.6: Decomposability cardinal of a direct sum: Canonical concrete corners, bounded/measured direct products, projection generator and decomposability cardinals, homogeneous components and magnitude (hard)
  • Theorem 9.8: Projection generators and countable dependence: Actual projection-generator cardinal, strong topology on Boolean projections and complete generated closure membership (hard)
  • Lemma 9.10: Homogeneous types are zero or infinite: Canonical concrete corners, bounded/measured direct products, projection generator and decomposability cardinals, homogeneous components and magnitude (hard)
  • Lemma 9.11: Every projection contains a homogeneous part: Canonical concrete corners, bounded/measured direct products, projection generator and decomposability cardinals, homogeneous components and magnitude (hard)
  • Lemma 9.12: Homogeneous decomposition: Canonical concrete corners, bounded/measured direct products, projection generator and decomposability cardinals, homogeneous components and magnitude (hard)
  • Lemma 9.14: Disjoint homogeneous components sum to one: Canonical concrete corners, bounded/measured direct products, projection generator and decomposability cardinals, homogeneous components and magnitude (hard)
  • Lemma 9.15: A sigma-finite component of infinite type is homogeneous: Canonical concrete corners, bounded/measured direct products, projection generator and decomposability cardinals, homogeneous components and magnitude (hard)
  • Theorem 9.16: Finite-trace homogeneous uniqueness: Canonical concrete corners, bounded/measured direct products, projection generator and decomposability cardinals, homogeneous components and magnitude (hard)
  • Theorem 9.17: Classification by magnitudes and weighted atom counts: Canonical concrete corners, bounded/measured direct products, projection generator and decomposability cardinals, homogeneous components and magnitude (hard)
  • Proposition 9.18: Bernoulli tensor building blocks: Specified Bernoulli C*-inductive-limit block, incomplete tensor Hilbert space, GNS representation, von Neumann closure and product state; compatible measured direct sums (hard)
  • Corollary 9.19: Normalized homogeneous algebras are Bernoulli tensor blocks: Specified Bernoulli C*-inductive-limit block, incomplete tensor Hilbert space, GNS representation, von Neumann closure and product state; compatible measured direct sums (hard)
  • Theorem 9.20: Maharam theorem for von Neumann measure algebras: Specified Bernoulli C*-inductive-limit block, incomplete tensor Hilbert space, GNS representation, von Neumann closure and product state; compatible measured direct sums (hard)
  • Corollary 9.21: Classification after forgetting trace: Specified Bernoulli C*-inductive-limit block, incomplete tensor Hilbert space, GNS representation, von Neumann closure and product state; compatible measured direct sums (hard)
  • Proposition 9.23: C*-tensor block is continuous functions on a Cantor cube: Specified Bernoulli C*-inductive-limit block, incomplete tensor Hilbert space, GNS representation, von Neumann closure and product state; compatible measured direct sums (hard)
  • Corollary 9.24: Von Neumann tensor block is the classical Bernoulli L-infinity: Specified Bernoulli C*-inductive-limit block, incomplete tensor Hilbert space, GNS representation, von Neumann closure and product state; compatible measured direct sums (hard)
  • Corollary 9.25: Countable Bernoulli block is the Lebesgue interval algebra: Specified Bernoulli C*-inductive-limit block, incomplete tensor Hilbert space, GNS representation, von Neumann closure and product state; compatible measured direct sums (hard)
  • Example 2.4: a semifinite nonlocalizable measure: Countable/co-countable counting L-infinity inclusion and measure-preserving conditional expectation (hard)
  • Remark 4.8(3): unproved set-theoretic equivalence: The paper-specific meaning of measurable cardinal in the announced equivalence (source-ambiguity)
  • Remark 7.26: projection functor preserves direct sums: Actual measured/unmeasured categories and the constructed projection functor, morphism restrictions and direct-sum comparison (hard)
  • Unnumbered Dedekind and Stonean characterization: Canonical L-infinity Gelfand spectrum, norm-preserving real/complex Banach injectivity, and concrete 0/infinity-measure realization (hard)
  • Example 8.2: normal integration does not imply W*: The specific Dixmier quotient of bounded Borel functions by the meager-support ideal, its norm/order and trivial integration weight (hard)
  • Remark 9.22: probability-algebra refinement: Specified Bernoulli C*-inductive-limit block, incomplete tensor Hilbert space, GNS representation, von Neumann closure and product state; compatible measured direct sums (hard)
  • Unnumbered extension after Corollary 9.25: Specified Bernoulli C*-inductive-limit block, incomplete tensor Hilbert space, GNS representation, von Neumann closure and product state; compatible measured direct sums (hard)
  • Remark 9.22: classical description of L-infinity star isomorphisms: Specified Bernoulli C*-inductive-limit block, incomplete tensor Hilbert space, GNS representation, von Neumann closure and product state; compatible measured direct sums (hard)

Selected references

  • Abelian von Neumann algebras, measure algebras and L^\infty-spaces, arXiv:2108.06406v2, https://arxiv.org/abs/2108.06406v2
15 thms2 active usersReviewed
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Quantum Information·Captain: Goku

Generalised Coupling and An Elementary Algorithm for the Quantum Schur TransformResearch Paper

Motivation

The quantum Schur transform is a fundamental building block that maps the computational basis to a coupled basis consisting of irreducible representations of the unitary and symmetric groups. Equivalently, it may be regarded as a change of basis from the computational basis to a simultaneous spin eigenbasis of Permutational Quantum Computing (PQC) [Quantum Inf. Comput., 10, 470-497 (2010)]. By adopting the latter perspective, we present a transparent algorithm for implementing the qubit quantum Schur transform which uses O(log⁡(n))O(\log(n))O(log(n)) ancillas and can be decomposed into a sequence of O(n3log⁡(n)log⁡(nϵ))O(n^3\log(n)\log(\frac{n}{\epsilon}))O(n3log(n)log(ϵn​)) Clifford + T gates, where ϵ\epsilonϵ is the accuracy of the algorithm in terms of the trace norm. We discuss the necessity for some applications of implementing this operation as a unitary rather than an isometry, as is often presented. By studying the associated Schur states, which consist of qubits coupled via Clebsch-Gordan coefficients, we introduce the notion of generally coupled quantum states. We present six conditions, which in different combinations ensure the efficient preparation of these states on a quantum computer or their classical simulability (in the sense of computational tractability). It is shown that Wigner 6-j symbols and SU(N) Clebsch-Gordan coefficients naturally fit our framework. Finally, we investigate unitary transformations which preserve the class of computationally tractable states.

This mission is the statement-level formalization of Generalised Coupling and An Elementary Algorithm for the Quantum Schur Transform (arXiv:2305.04069v3). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

5 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is General coupling preserves normalization and orthogonality in M (§IV.A, unnumbered: generally coupled states are normalized and M-orthogonal, PDF p. 13). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

17 results of the paper are not stated yet, because the library lacks an interface they need:

  • Abstract / §V / Appendix A: clean qubit Schur transform with logarithmic ancillas: The compared maps and nuclear-norm error after spectator padding (source-ambiguity)
  • §III.A, Algorithms 1–2: original clean Schur synthesis: Total padded local pre-mapping permutations and original clean source gate schedule (hard)
  • §III.B: PQC bases block diagonalize the two Schur–Weyl actions: All-tree SU(2) coupled basis with both irreducible Schur–Weyl actions (hard)
  • §III.C, Algorithms 3–4: general clean PQC synthesis: Complete general-tree CG blocks, total local ordering, routing and gate lists (hard)
  • §IV.B, unnumbered: GC1–GC6 imply computational tractability: Uniform exact amplitude-evaluation and exact classical-sampling model for GC3–GC6 (source-ambiguity)
  • §IV.C, unnumbered: efficient preparation without GC4: Computational model for coefficient-driven unitary synthesis and its target accuracy (source-ambiguity)
  • §IV.C, unnumbered: logarithmic ancillas for sequential individual-state preparation: Live-register schedule attached to sequential individual-state preparation (hard)
  • §IV.D, unnumbered: fixed-rank SU(N) coupling conditions and preparation: Phase-fixed GT CG coefficients and uniform exact evaluation/preparation semantics (source-ambiguity)
  • §IV.D, unnumbered: fixed-dimensional qudit extension of PQC circuits: All-label fixed-d qudit pre-mapping and clean SU(d)-CG gate schedule (hard)
  • §IV.E, Eqs.(52)–(57): Wigner coupling conditions and failure of GC4: Normalized finite Racah tensor with admissible triangular domains and uniform coefficient programs (hard)
  • §V, Eqs.(77)–(78): exact total qubit counts: Concrete original and compressed register-liveness traces whose maxima are counted (hard)
  • Lemma VI.2: one Hadamard preserves a CT family: Operational CT-family model with exact amplitudes and conditional sampling (source-ambiguity)
  • §VI, unnumbered: one arbitrary computable single-qubit gate preserves CT: Uniform computable one-qubit coefficient access in an exact CT-family model (source-ambiguity)
  • Claim A.1: O(n^3) two-level rotations for Schur transform: Concrete source-compatible sequential pre-map and clean two-level circuit target (hard)
  • Claim A.3: O(n^6) two-level rotations for general PQC unitary: Concrete arbitrary-tree source unitary and active two-level decomposition interface (hard)
  • Claim A.4: O(n^3) two-level rotations for individual PQC state: Concrete general PQC state amplitudes and their active two-level preparation interface (hard)
  • Appendix A, Table II: remaining Clifford+T bounds: Separate nuclear-norm circuit-map and prepared-state approximation conventions (source-ambiguity)

Selected references

  • Generalised Coupling and An Elementary Algorithm for the Quantum Schur Transform, arXiv:2305.04069v3, https://arxiv.org/abs/2305.04069v3
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Quantum Information·Captain: Goku

Efficient Clifford+T approximation of single-qubit operatorsResearch Paper

Motivation

We give an efficient randomized algorithm for approximating an arbitrary element of SU(2)SU(2)SU(2) by a product of Clifford+TTT operators, up to any given error threshold ϵ>0\epsilon>0ϵ>0. Under a mild hypothesis on the distribution of primes, the algorithm's expected runtime is polynomial in log⁡(1/ϵ)\log(1/\epsilon)log(1/ϵ). If the operator to be approximated is a zzz-rotation, the resulting gate sequence has TTT-count K+4log⁡2(1/ϵ)K+4\log_2(1/\epsilon)K+4log2​(1/ϵ), where KKK is approximately equal to 101010. We also prove a worst-case lower bound of K+4log⁡2(1/ϵ)K+4\log_2(1/\epsilon)K+4log2​(1/ϵ), where K=−9K=-9K=−9, so that our algorithm is within an additive constant of optimal for certain zzz-rotations. For an arbitrary member of SU(2)SU(2)SU(2), we achieve approximations with TTT-count K+12log⁡2(1/ϵ)K+12\log_2(1/\epsilon)K+12log2​(1/ϵ). By contrast, the Solovay-Kitaev algorithm achieves TTT-count O(log⁡c(1/ϵ))O(\log^c(1/\epsilon))O(logc(1/ϵ)), where ccc is approximately 3.973.973.97.

This mission is the statement-level formalization of Efficient Clifford+T approximation of single-qubit operators (arXiv:1212.6253v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

12 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Units and totally nonnegative unit squares (Lemma 10: units and totally nonnegative unit squares, PDF p. 4). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

9 results of the paper are not stated yet, because the library lacks an interface they need:

  • Abstract and §1: efficient ancilla-free Clifford+T approximation (seed): Uniform prime-candidate/seed law and a real-input access convention for the bundled efficient compiler. (source-ambiguity)
  • Theorem 12: relative norm equation and randomized construction: Binary-cost randomized norm-solver execution on coefficient-encoded Z[omega]. (hard)
  • Theorem 22: candidate count and efficient sampling: Full printed epsilon>0 candidate enumerator and efficient uniform sampler outside the intended small-error geometry. (source-ambiguity)
  • Algorithm 23: returned-circuit correctness: Successful finite execution trace joining candidate generation, norm-solver attempts, checked acceptance and exact gate synthesis. (hard)
  • §8.1: successful-output T-count bounds: Source exact-synthesis/normalization output interface with denominator exponent and actual returned-word T-count. (hard)
  • Remark 28: fixed Clifford+T conjugation: Uniform slope-four z-rotation approximation family before fixed-word conjugation. (source-ambiguity)
  • §8.2 and Hypothesis 29: expected runtime: Uniform pointwise probability law for Hypothesis 29 and source-specific bit-runtime input model. (source-ambiguity)
  • §8.3: seeding and T-count overhead: Specified angle-seed and bounded-T-count-word seed laws with successful-seed probability and restart cutoff. (source-ambiguity)
  • §10: additive overclocking claim: Quantified admissible additive decrement and successful-beta fraction for overclocked sampling. (source-ambiguity)

Selected references

  • Efficient Clifford+T approximation of single-qubit operators, arXiv:1212.6253v2, https://arxiv.org/abs/1212.6253v2
14 thms2 active usersReviewed
🏆Completed
Quantum Information·Captain: Goku

Entropic Fluctuations in Statistical Mechanics II. Quantum Dynamical SystemsResearch Paper

Motivation

The celebrated Evans-Searles, respectively Gallavotti-Cohen, fluctuation theorem concerns certain universal statistical features of the entropy production rate of a classical system in a transient, respectively steady, state. In this paper, we consider and compare several possible extensions of these fluctuation theorems to quantum systems. In addition to the direct two-time measurement approach whose discussion is based on (LMP 114:32 (2024)), we discuss a variant where measurements are performed indirectly on an auxiliary system called ancilla, and which allows to retrieve non-trivial statistical information using ancilla state tomography. We also show that modular theory provides a way to extend the classical notion of phase space contraction rate to the quantum domain, which leads to a third extension of the fluctuation theorems. We further discuss the quantum version of the principle of regular entropic fluctuations, introduced in the classical context in (Nonlinearity 24, 699 (2011)). Finally, we relate the statistical properties of these various notions of entropy production to spectral resonances of quantum transfer operators. The obtained results shed a new light on the nature of entropic fluctuations in quantum statistical mechanics.

This mission is the statement-level formalization of Entropic Fluctuations in Statistical Mechanics II. Quantum Dynamical Systems (arXiv:2409.15485v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

8 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Finite ancilla tomography recovers the entropic functional (finite-ancilla-tomography, PDF p. 13). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

28 results of the paper are not stated yet, because the library lacks an interface they need:

  • theorem-2.1: An unambiguous corrected source statement for theorem-2.1 (source-ambiguity)
  • continuous-2tm-extension: An unambiguous corrected source statement for continuous-2tm-extension (source-ambiguity)
  • proposition-2.2: The actual open-system Mat2(O) perturbed dynamics and Araki–Connes ancilla functional (hard)
  • proposition-2.3: Canonical modular spectral probability and extended Araki entropy (hard)
  • theorem-2.5: An unambiguous corrected source statement for theorem-2.5 (source-ambiguity)
  • proposition-2.6: The quantum 2tm law and its speed-t full/local LDP (hard)
  • weak-quantum-rigidity: Canonical extension of 2tm laws to singular NESS and reservoir modular averaging (hard)
  • proposition-2.9: Unique O-valued analytic Connes extension and the NESS characteristic law for every real t (hard)
  • ancilla-analytic-continuation: Conjugated-parameter cocycle product evaluated in an arbitrary singular algebraic state (hard)
  • proposition-2.11: The analytic perturbation orbit and constructed Dyson cocycle of an open system (hard)
  • proposition-2.12: Natural-cone comparison for the actual evolved reference and ancilla functional (hard)
  • two-time-comparison: Modular Cesaro definition of 2tm statistics on evolved reference states (hard)
  • ancilla-exchange-of-limits: Actual real-alpha ancilla functionals in a general NESS open system (hard)
  • classical-exchange-of-limits: An unambiguous corrected source statement for classical-exchange-of-limits (source-ambiguity)
  • classical-discrete-analogue: An unambiguous corrected source statement for classical-discrete-analogue (source-ambiguity)
  • proposition-2.17: Relative Tomita construction and time-covariant Connes cocycle in the GNS algebra (hard)
  • theorem-2.18: Unbounded modular logarithms and bounded relative Hamiltonian derived from Qu1; canonical quantum Cesaro NESS production positivity (p.26 Remark 1) (hard)
  • open-system-entropy-observable: Unbounded logarithmic modular perturbation formula and modular derivation domain (hard)
  • reference-functional-identity: The three canonically defined algebraic quantum functionals (hard)
  • proposition-3.1: Canonical standard Liouvillean and quantum transfer group from the actual Connes family (hard)
  • ancilla-generator-similarity: Modular spectral powers acting on the actual closed ancilla generator domain (hard)
  • proposition-3.2: The distinct physical quantum transfer groups and finite-time functionals (hard)
  • theorem-4.3: Canonical 1/2-Liouvillean weighted resolvent, D inverse domain, and algebraic NESS state (hard)
  • theorem-4.4: Deform2 on actual quantum groups, singular NESS evaluations, and modular-power domains (hard)
  • theorem-4.5: Deform3 and the physical cumulants of the genuine modular resonance family (hard)
  • alternative-ancilla-resonance: An unambiguous corrected source statement for alternative-ancilla-resonance (source-ambiguity)
  • proposition-4.6: Bounded weighted composition on L2 classes for a non-measure-preserving flow (hard)
  • classical-transfer-representations: The L2 weighted transfer group and its actual generator, not just its scalar integral (hard)

Selected references

  • Entropic Fluctuations in Statistical Mechanics II. Quantum Dynamical Systems, arXiv:2409.15485v2, https://arxiv.org/abs/2409.15485v2
10 thms2 active usersReviewed
Quantum Information·Captain: Goku

On entropic quantities related to the classical capacity of infinite dimensional quantum channelsResearch Paper

Motivation

In this paper we consider the χ\chiχ-function (the Holevo capacity of constrained channel) and the convex closure of the output entropy for arbitrary infinite dimensional channel. It is shown that the χ\chiχ-function of an arbitrary channel is a concave lower semicontinuous function on the whole state space, having continuous restriction to any set of continuity of the output entropy. The explicit representation for the convex closure of the output entropy is obtained and its properties are explored. It is shown that the convex closure of the output entropy coincides with the convex hull of the output entropy on the convex set of states with finite output entropy. Similarly to the case of the χ\chiχ-function, it is proved that the convex closure of the output entropy has continuous restriction to any set of continuity of output entropy. Some applications of these results to the theory of entanglement are discussed. The obtained properties of the convex closure of the output entropy make it possible to generalize to the infinite dimensional case the convex duality approach to the additivity problem.

This mission is the statement-level formalization of On entropic quantities related to the classical capacity of infinite dimensional quantum channels (arXiv:quant-ph/0411091v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

27 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is §6, unnumbered Theorem: convex-duality additivity equivalence and consequences (§6, unnumbered Theorem: convex-duality additivity equivalence and consequences, PDF p. 19). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

1 results of the paper are not stated yet, because the library lacks an interface they need:

  • Section 7, unnumbered energy-continuity assertion: The Hamiltonian domain intended by the unqualified Section 7 mean-energy-continuity sentence. (source-ambiguity)

Selected references

  • On entropic quantities related to the classical capacity of infinite dimensional quantum channels, arXiv:quant-ph/0411091v1, https://arxiv.org/abs/quant-ph/0411091v1
32 thms2 active usersReviewed
Quantum Information·Captain: Goku

Entanglement of formation for symmetric Gaussian statesResearch Paper

Motivation

We show that for a fixed amount of entanglement, two-mode squeezed states are those that maximize Einstein-Podolsky-Rosen-like correlations. We use this fact to determine the entanglement of formation for all symmetric Gaussian states corresponding to two modes. This is the first instance in which this measure has been determined for genuine continuous variable systems.

This mission is the statement-level formalization of Entanglement of formation for symmetric Gaussian states (arXiv:quant-ph/0304042v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

9 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Symmetric Gaussian entanglement of formation (Proposition 2: entanglement of formation of symmetric two-mode Gaussian states, PDF p. 4). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Selected references

  • Entanglement of formation for symmetric Gaussian states, arXiv:quant-ph/0304042v1, https://arxiv.org/abs/quant-ph/0304042v1
12 thms2 active usersReviewed
🏆Completed
Quantum Information·Captain: Goku

Sufficiency in quantum statistical inferenceResearch Paper

Motivation

This paper attempts to develop a theory of sufficiency in the setting of non-commutative algebras parallel to the ideas in classical mathematical statistics. Sufficiency of a coarse-graining means that all information is extracted about the mutual relation of a given family of states. In the paper sufficient coarse-grainings are characterized in several equivalent ways and the non-commutative analogue of the factorization theorem is obtained. Among the applications the equality case for the strong subadditivity of the von Neumann entropy, the Imoto-Koashi theorem and exponential families are treated. The setting of the paper allows the underlying Hilbert space to be infinite dimensional.

This mission is the statement-level formalization of Sufficiency in quantum statistical inference (arXiv:math-ph/0412093v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

10 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Lemma 1: countable common-null-set subfamily (Lemma 1: countable common-null-set subfamily, PDF p. 4). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

29 results of the paper are not stated yet, because the library lacks an interface they need:

  • Unnumbered: classical minimal sufficient sigma-algebra: An additional reference-measure condition for the claimed minimal sufficient density algebra (source-ambiguity)
  • Theorem 1: five criteria for a sufficient subalgebra: Natural-cone PA, Connes cocycles, and the computed generalized conditional expectation (hard)
  • Lemma 3: monotonicity of canonical cone overlap: Positive trace-class square-root realization and trace of the product of Hilbert-Schmidt square roots (hard)
  • Lemma 4 and its concluding converse: equality in overlap monotonicity: Support-zero spectral imaginary powers, the actual Heisenberg adjoint, and canonical cone overlap (hard)
  • Proposition 3: classical factorization criterion: Common-reference almost-everywhere factorization (source-ambiguity)
  • Unnumbered: sufficiency survives support compression: Computed support-corner algebras and their normal 2-positive compression/extension maps (hard)
  • Unnumbered: modular characterization of recovery fixed algebras: Constructed generalized dual, modular group, and fixed-point star algebras (hard)
  • Theorem 2: six equivalent sufficiency and canonical-recovery conditions: Canonical generalized dual and computed multiplicative-domain image and recovery fixed algebras (hard)
  • Remark after Theorem 2: relative-entropy equality iff canonical recovery: Computed canonical normal recovery channel for finite extended-relative-entropy equality (hard)
  • Unnumbered: noncommuting experiments have no sufficient measurement: The computed minimal sufficient algebra and general commutative-domain sufficient measurements (hard)
  • Equation (16): modular-invariant reference-state factorization: Canonical type-I trace densities and an affiliated positive central correction (hard)
  • Theorem 3: noncommutative factorization criterion (seed main result): Canonical modular-invariant density factorization with a computed central affiliated factor (hard)
  • Unnumbered: cocycle-generated minimal sufficient algebra: Cocycle-generated minimal sufficient algebra, modular invariance, and its canonical S-factorization (hard)
  • Theorem 4: maximality of canonical S-factorization: The canonical S-factors and a possibly unbounded affiliated maximality correction R0 (hard)
  • Unnumbered: canonical direct-sum tensor S-decomposition and uniqueness: A canonical countable orthogonal completed-Hilbert tensor decomposition and compatible uniqueness relation (hard)
  • Theorem 5: sufficient channel block structure and induced S-decomposition: Canonical source and target S-blocks, their normal right maps, and the extended positive-weight dual (hard)
  • Corollary 1: Kraus block criterion for finite-dimensional sufficiency: The actual finite-dimensional canonical S-decomposition and operator transport into its tensor blocks (hard)
  • Corollary 2: claimed nondisturbance Kraus commutation criterion: A correct condition for right-factor stationary states (source-ambiguity)
  • Example 4: claimed local unique entropy-constrained exponential fit: Nondegeneracy for the local moment map and multiplier uniqueness (source-ambiguity)
  • Equations (23)–(25): variationally perturbed state, Gibbs formula and support: Normalized modularly perturbed states and their unnormalized positive vector functionals (hard)
  • Theorem 6 [15]: sufficiency criteria for an exponential family: Normalized modularly perturbed states and their unnormalized positive vector functionals (hard)
  • Unnumbered: minimum free energy, analyticity and derivative identity: Normalized modularly perturbed states and their unnormalized positive vector functionals (hard)
  • Theorem 7: sufficient coarse-grainings of exponential families: Normalized modularly perturbed states and their unnormalized positive vector functionals (hard)
  • Remark after Theorem 7: matrix logarithmic sufficiency criterion: A computed faithful quantum exponential family and correctly typed logarithmic trace-dual criterion (hard)
  • Corollary 3: commutative sufficient subalgebras of exponential families: Normalized modularly perturbed states and their unnormalized positive vector functionals (hard)
  • Theorem 8: countable Markov block structure at SSA equality: A countable completed-Hilbert Markov block decomposition of B and transported density equality (hard)
  • Unnumbered: pure-state SSA equality yields a single product block: Support-level tensor splitting of a purification, with actual transported product vectors (hard)
  • Equation (30): claimed non-atomic direct-integral normal density: A valid normal-state model for a non-atomic direct integral (source-ambiguity)
  • Appendix: support-corner dual and generalized conditional expectation (31): Canonical support-corner generalized dual and its normal predual, including the CP specialization (hard)

Selected references

  • Sufficiency in quantum statistical inference, arXiv:math-ph/0412093v1, https://arxiv.org/abs/math-ph/0412093v1
14 thms2 active usersReviewed
Quantum Information·Captain: Goku

Classical capacity of bosonic broadcast communication and a new minimum output entropy conjectureResearch Paper

Motivation

Previous work on the classical information capacities of bosonic channels has established the capacity of the single-user pure-loss channel, bounded the capacity of the single-user thermal-noise channel, and bounded the capacity region of the multiple-access channel. The latter is a multi-user scenario in which several transmitters seek to simultaneously and independently communicate to a single receiver. We study the capacity region of the bosonic broadcast channel, in which a single transmitter seeks to simultaneously and independently communicate to two different receivers. It is known that the tightest available lower bound on the capacity of the single-user thermal-noise channel is that channel's capacity if, as conjectured, the minimum von Neumann entropy at the output of a bosonic channel with additive thermal noise occurs for coherent-state inputs. Evidence in support of this minimum output entropy conjecture has been accumulated, but a rigorous proof has not been obtained. In this paper, we propose a new minimum output entropy conjecture that, if proved to be correct, will establish that the capacity region of the bosonic broadcast channel equals the inner bound achieved using a coherent-state encoding and optimum detection. We provide some evidence that supports this new conjecture, but again a full proof is not available.

This mission is the statement-level formalization of Classical capacity of bosonic broadcast communication and a new minimum output entropy conjecture (arXiv:0706.3416v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

10 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Conditional coherent-state capacity region (Section IV, Eqs. (1), (16)-(17); PDF pp.1,3-5, PDF p. 1). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

1 results of the paper are not stated yet, because the library lacks an interface they need:

  • Section V / Figure 4, PDF pp.6-7: The exact MAC photon-budget/power-allocation constraint defining the envelope compared with the coherent bosonic broadcast region. (source-ambiguity)

Selected references

  • Classical capacity of bosonic broadcast communication and a new minimum output entropy conjecture, arXiv:0706.3416v1, https://arxiv.org/abs/0706.3416v1
14 thms2 active usersReviewed
Quantum Information·Captain: Goku

The bosonic minimum output entropy conjecture and Lagrangian minimizationResearch Paper

Motivation

We introduce a new form for the bosonic channel minimal output entropy conjecture, namely that among states with equal input entropy, the thermal states are the ones that have slightest increase in entropy when sent through a infinitesimal thermalizing channel. We then detail a strategy to prove the conjecture through variational techniques. This would lead to the calculation of the classical capacity of a communication channel subject to thermal noise. Our strategy detects input thermal ensembles as possible solutions for the optimal encoding of the channel, lending support to the conjecture. However, it does not seem to be able to exclude the possibility that other input ensembles can attain the channel capacity.

This mission is the statement-level formalization of The bosonic minimum output entropy conjecture and Lagrangian minimization (arXiv:0906.2758v3). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

13 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Thermal and displaced thermal stationary witnesses and local output-entropy minima (Unnumbered main result: thermal stationarity and local output-entropy minima, PDF p. 1). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

11 results of the paper are not stated yet, because the library lacks an interface they need:

  • Section I: finite conjecture: A proved unrestricted global vacuum-output entropy bound, rather than its conjecture. (hard)
  • Section I: infinitesimal fixed-entropy conjecture: A proved global fixed-entropy instantaneous-rate inequality. (hard)
  • Section VIII: claimed equivalence: A reverse implication from the finite pure-input minimum to the positive-entropy rate conjecture. (source-ambiguity)
  • Section II, Eq.(5): entropy trace expansion: A source-specified trace differentiability domain and controlled second-order entropy remainder. (source-ambiguity)
  • Section IV, Eqs.(6)–(8): all-cutoff stationarity: An exact N-to-N+1 cutoff dynamics, its rectangular dual, and order-of-time convention. (source-ambiguity)
  • Section IV: energy-minimum attainment in a connected minimum manifold: A source-supported attainment condition on every connected minimum component. (source-ambiguity)
  • Section V, Eqs.(9)–(13): double-stationary classification: Consistent complete primal/dual stationarity equations and common unbounded domains for all candidate solutions. (source-ambiguity)
  • Section VI, Eq.(14): full thermal perturbation expansion: Norm/domain and remainder bound for the complete infinite-dimensional Eq.(14). (source-ambiguity)
  • Section VII: attributed stationarity sufficiency: A valid second-order or convexity sufficiency hypothesis for Eq.(16). (source-ambiguity)
  • Appendix 1: cutoff-independent stationary solutions and their limit: Consistent cutoff CCR, truncated Gibbs normalization, and a stationary-limit theorem. (source-ambiguity)
  • Appendix 2: unqualified boundary asymptotic coefficient: A pinned, correct general boundary leakage coefficient and its trace domain. (source-ambiguity)

Selected references

  • The bosonic minimum output entropy conjecture and Lagrangian minimization, arXiv:0906.2758v3, https://arxiv.org/abs/0906.2758v3
16 thms2 active usersReviewed
🏆Completed
Quantum Information·Captain: Goku

Quantum mechanics in phase space: The Schr"odinger and the Moyal representationsResearch Paper

Motivation

We present a phase space formulation of quantum mechanics in the Schr"odinger representation and derive the associated Weyl pseudo-differential calculus. We prove that the resulting theory is unitarily equivalent to the standard "configuration space" formulation and show that it allows for a uniform treatment of both pure and mixed quantum states. In the second part of the paper we determine the unitary transformation (and its infinitesimal generator) that maps the phase space Schr"odinger representation into another (called Moyal) representation, where the wave function is the cross-Wigner function familiar from deformation quantization. Some features of this representation are studied, namely the associated pseudo-differential calculus and the main spectral and dynamical results. Finally, the relation with deformation quantization is discussed.

This mission is the statement-level formalization of Quantum mechanics in phase space: The Schr"odinger and the Moyal representations (arXiv:1209.1850v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

16 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Unitary equivalence with the window subspace (Abstract main result: unitary equivalence with configuration space, PDF p. 1). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

9 results of the paper are not stated yet, because the library lacks an interface they need:

  • §3, unnumbered: mixed-state eigenspace and convex probability claim: Consistent mixed-state observable and projection conventions (source-ambiguity)
  • §3, unnumbered: projection and collapse probability claim: Consistent mixed-state observable and projection conventions (source-ambiguity)
  • Theorem 4.6: Continuous exterior distribution product, partial-Fourier Weyl kernel, and independent double-phase symbol transform (hard)
  • Theorem 4.7: Schwartz tensor/contraction maps and their correct distribution transposes (hard)
  • Corollary 4.8: Kernel-defined Weyl operators on Schwartz inputs and nonzero window-contraction interface (hard)
  • Theorem 5.7: Independent Weyl-symbol submersion pullback and Schwartz/distribution U conjugation (hard)
  • Corollary 5.10: Distribution-valued time derivative and independent star-product Hamiltonian action (hard)
  • Corollary 5.11: Generic tempered Weyl/star operators and Schwartz-domain U/window intertwiners (hard)
  • Corollary 5.9: Independently constructed tempered-symbol Moyal product and Moyal operator (hard)

Selected references

  • Quantum mechanics in phase space: The Schr"odinger and the Moyal representations, arXiv:1209.1850v1, https://arxiv.org/abs/1209.1850v1
20 thms2 active usersReviewed
Machine LearningOperations ResearchOptimization+1·Captain: mikedeng1

Accelerated MM Algorithms for Ranking Scores Inference from Comparison Data: Rescaled MM for Bradley–Terry MAP Estimation Contracts the Log-Posterior Gap at a Rate Set by Algebraic ConnectivityResearch Paper

Ranking from paired comparisons

Paired-comparison data (which of two items a user clicked, which of two players won a game, which of two products a respondent preferred) are summarised by ranking scores, one real number per item. The Bradley–Terry model (Bradley and Terry, 1952) is the standard statistical model for such scores, and its parameters are estimated by maximum likelihood or by maximum a posteriori (MAP) estimation. The workhorse for both is the MM algorithm (minorize–maximize), systematised for the Bradley–Terry family by Hunter (2004); the MAP version with a Gamma prior is due to Caron and Doucet (2012).

Vojnović, Yun and Zhou (arXiv:1901.00150v3) give the first rate-of-convergence analysis of these algorithms that depends on the structure of the comparison data. They find that the classic MAP iteration can be arbitrarily slow when the prior is weak, and that a simple rescaling of each iterate removes the slowdown. This mission formalizes the rate of the rescaled MM algorithm, the paper's Corollary 4.2.

Setting

There are nnn items. For i≠ji\ne ji=j, di,j∈Nd_{i,j}\in\mathbb Ndi,j​∈N is the number of comparisons in which item iii beat item jjj. The co-occurrence matrix MMM has entries mi,j=di,j+dj,im_{i,j}=d_{i,j}+d_{j,i}mi,j​=di,j​+dj,i​ for i≠ji\ne ji=j and mi,i=0m_{i,i}=0mi,i​=0. Three quantities of MMM enter the rate:

  • d(M)=∥M∥∞=max⁡i∑jmi,jd(M)=\|M\|_\infty=\max_i\sum_j m_{i,j}d(M)=∥M∥∞​=maxi​∑j​mi,j​, the maximum number of comparisons of an item;
  • the Laplacian LM=DM−ML_M=D_M-MLM​=DM​−M, where DMD_MDM​ is diagonal with the row sums of MMM;
  • the algebraic connectivity a(M)=λ2(LM)a(M)=\lambda_2(L_M)a(M)=λ2​(LM​), the second smallest eigenvalue of LML_MLM​, which is positive exactly when the comparison graph is connected for n≥2n\ge2n≥2.

The parameter is w∈Rnw\in\mathbb R^nw∈Rn, with item strengths θi=ewi\theta_i=e^{w_i}θi​=ewi​, and item iii beats item jjj with probability ewi/(ewi+ewj)e^{w_i}/(e^{w_i}+e^{w_j})ewi​/(ewi​+ewj​). The log-likelihood and the log-prior of independent Gamma(α,β)\mathrm{Gamma}(\alpha,\beta)Gamma(α,β) priors on the ewie^{w_i}ewi​ are

ℓ(w)=∑i=1n∑j≠idi,j(wi−log⁡(ewi+ewj)),ℓ0(w)=∑i=1n((α−1)wi−βewi).\ell(w)=\sum_{i=1}^n\sum_{j\ne i}d_{i,j}\bigl(w_i-\log(e^{w_i}+e^{w_j})\bigr),\qquad \ell_0(w)=\sum_{i=1}^n\bigl((\alpha-1)w_i-\beta e^{w_i}\bigr).ℓ(w)=i=1∑n​j=i∑​di,j​(wi​−log(ewi​+ewj​)),ℓ0​(w)=i=1∑n​((α−1)wi​−βewi​).

The log-a posteriori function is ρ=ℓ+ℓ0\rho=\ell+\ell_0ρ=ℓ+ℓ0​, and the MAP estimate w∗w^*w∗ maximizes it. The MM algorithm maximizes, at each step, the surrogate ρ(x;w(t))=ℓ(x;w(t))+ℓ0(x)\rho(x;w^{(t)})=\ell(x;w^{(t)})+\ell_0(x)ρ(x;w(t))=ℓ(x;w(t))+ℓ0​(x), where

ℓ(x;y)=∑i=1n∑j≠idi,j(xi−exi+exjeyi+eyj−log⁡(eyi+eyj)+1)\ell(x;y)=\sum_{i=1}^n\sum_{j\ne i}d_{i,j}\Bigl(x_i-\frac{e^{x_i}+e^{x_j}}{e^{y_i}+e^{y_j}}-\log(e^{y_i}+e^{y_j})+1\Bigr)ℓ(x;y)=i=1∑n​j=i∑​di,j​(xi​−eyi​+eyj​exi​+exj​​−log(eyi​+eyj​)+1)

lies below ℓ\ellℓ and touches it at x=yx=yx=y. The rescaling is Π(x)=x+c(x)1\Pi(x)=x+c(x)\mathbf 1Π(x)=x+c(x)1 with c(x)=log⁡(α−1βn)−log⁡∑iexic(x)=\log\bigl(\tfrac{\alpha-1}{\beta}n\bigr)-\log\sum_i e^{x_i}c(x)=log(βα−1​n)−log∑i​exi​. It shifts all scores by a common constant so that ∑iθi=n(α−1)/β\sum_i\theta_i=n(\alpha-1)/\beta∑i​θi​=n(α−1)/β. The rescaled MM algorithm (Algorithm 1) is w(t+1)=Π(x′)w^{(t+1)}=\Pi(x')w(t+1)=Π(x′) with x′x'x′ a maximizer of ρ(⋅ ;w(t))\rho(\cdot\,;w^{(t)})ρ(⋅;w(t)). Finally Wω={w:∥w∥∞≤ω}W_\omega=\{w:\|w\|_\infty\le\omega\}Wω​={w:∥w∥∞​≤ω} and cω=1/(e−ω+eω)2c_\omega=1/(e^{-\omega}+e^{\omega})^2cω​=1/(e−ω+eω)2.

Formalization targets

Goal: Corollary 4.2

If the MAP point w∗w^*w∗, the iterate w(t)w^{(t)}w(t) (an output of Π\PiΠ) and the virtual gradient point all lie in WωW_\omegaWω​, then

ρ(w∗)−ρ(w(t+1))≤(1−αM,ω,β)(ρ(w∗)−ρ(w(t))),αM,ω,β=2cωa(M)+2e−ωβ(1+e2ω)d(M)+2eωβ.\rho(w^*)-\rho(w^{(t+1)})\le\bigl(1-\alpha_{M,\omega,\beta}\bigr)\bigl(\rho(w^*)-\rho(w^{(t)})\bigr),\qquad \alpha_{M,\omega,\beta}=\frac{2c_\omega a(M)+2e^{-\omega}\beta}{(1+e^{2\omega})d(M)+2e^{\omega}\beta}.ρ(w∗)−ρ(w(t+1))≤(1−αM,ω,β​)(ρ(w∗)−ρ(w(t))),αM,ω,β​=(1+e2ω)d(M)+2eωβ2cω​a(M)+2e−ωβ​.

Milestones

The milestones follow the structure of the paper:

  • the minorization property of ℓ(x;y)\ell(x;y)ℓ(x;y);
  • the surrogate gap bounds ρ(x;y)−ρ(x)≥−δ2∥x−y∥2\rho(x;y)-\rho(x)\ge-\frac\delta2\|x-y\|^2ρ(x;y)−ρ(x)≥−2δ​∥x−y∥2 on [−ω,ω]n[-\omega,\omega]^n[−ω,ω]n with δ=12e2ωd(M)\delta=\frac12e^{2\omega}d(M)δ=21​e2ωd(M) (Lemmas 3.3, 3.5);
  • strong convexity and smoothness of −ρ-\rho−ρ on WωW_\omegaWω​ (Lemma 3.4) and the bound λn(LM)≤2d(M)\lambda_n(L_M)\le2d(M)λn​(LM​)≤2d(M);
  • condition (F1), smoothness of −ρ-\rho−ρ with μ=d(M)/2+eωβ\mu=d(M)/2+e^{\omega}\betaμ=d(M)/2+eωβ;
  • the Hessian bound ∇2(−ρ)⪰cωLM+e−ωβI\nabla^2(-\rho)\succeq c_\omega L_M+e^{-\omega}\beta I∇2(−ρ)⪰cω​LM​+e−ωβI on WωW_\omegaWω​;
  • the general PL lemma (Lemma 4.1) and its instance (F2), the PL inequality for −ρ-\rho−ρ with γ=cωa(M)+e−ωβ\gamma=c_\omega a(M)+e^{-\omega}\betaγ=cω​a(M)+e−ωβ on Wω∩{∇ρ⊤1=0}W_\omega\cap\{\nabla\rho^\top\mathbf 1=0\}Wω​∩{∇ρ⊤1=0};
  • the two properties of Π\PiΠ (Lemma 4.2): ρ(Π(w))≥ρ(w)\rho(\Pi(w))\ge\rho(w)ρ(Π(w))≥ρ(w) and ∇ρ(Π(w))⊤1=0\nabla\rho(\Pi(w))^\top\mathbf 1=0∇ρ(Π(w))⊤1=0;
  • the general one-step theorem for Π\PiΠ-transformed MM (Theorem 4.2), with rate γ/(μ+δ)\gamma/(\mu+\delta)γ/(μ+δ).

Significance

Without rescaling, the MAP rate of MM (the paper's Corollary 3.4) is 1−Ω(β/(β+d(M)))1-\Omega(\beta/(\beta+d(M)))1−Ω(β/(β+d(M))), and the paper shows this is tight on two items. For a weak prior, which is the usual choice in practice, convergence is therefore arbitrarily slow. The rescaled rate replaces β\betaβ by cωa(M)+e−ωβc_\omega a(M)+e^{-\omega}\betacω​a(M)+e−ωβ. It thus recovers, as β→0\beta\to0β→0, the maximum-likelihood rate governed by the algebraic connectivity of the comparison graph, at the cost of one normalisation per step. This explains the many-orders-of-magnitude speed-ups that the paper reports on real datasets.

The framework of §4.1 is stated for any objective, any surrogate and any map Π\PiΠ satisfying (F1), (F2), (P1), (P2). It applies to other generalized Bradley–Terry models (Rao–Kupper, Luce, Plackett–Luce) and to gradient descent. The results are proved on paper; none of them, and none of the Bradley–Terry objects, has a machine-checked proof that we know of. A formalization would also settle the points the printed statements leave implicit (see below).

Difficulty

The objective −ρ-\rho−ρ is not strongly convex with a useful constant on all of WωW_\omegaWω​: its curvature in the direction 1\mathbf 11 comes only from the prior and is of order β\betaβ. The natural argument (strong convexity of −ρ-\rho−ρ gives a PL inequality, and the PL inequality gives a linear rate) therefore yields only the slow β\betaβ-dependent rate. The faster rate needs a PL inequality that holds only on the points where ∇ρ⊥1\nabla\rho\perp\mathbf 1∇ρ⊥1 (Lemma 4.1). This uses the fact that the Hessian bound cωLM+e−ωβIc_\omega L_M+e^{-\omega}\beta Icω​LM​+e−ωβI does not couple 1\mathbf 11 with its orthogonal complement. The rescaling must then keep every iterate in that set without decreasing ρ\rhoρ.

All curvature bounds hold only on the box WωW_\omegaWω​, because βewi\beta e^{w_i}βewi​ is unbounded. The MM step is compared with a virtual gradient step, and that step must stay in the box.

Formalization scope

Parameters live in EuclideanSpace ℝ (Fin n) (items are 0-based); ∥⋅∥\|\cdot\|∥⋅∥ is the Euclidean norm and WωW_\omegaWω​ uses the sup norm. Counts are natural numbers and every sum runs over j≠ij\ne ij=i. Eigenvalues come from Mathlib's eigenvalues₀, and a(M)a(M)a(M) is 000 by convention for n<2n<2n<2. Gradients are Mathlib's gradient; the Hessian forms are second iterated Fréchet derivatives. The framework minimizes f=−ρf=-\rhof=−ρ, exactly as the paper does.

The goal fixes these points, relative to the printed statement:

  • α>1\alpha>1α>1 instead of α≥1\alpha\ge1α≥1, because Π\PiΠ takes log⁡((α−1)n/β)\log((\alpha-1)n/\beta)log((α−1)n/β);
  • w∗w^*w∗ is a maximizer of ρ\rhoρ lying in WωW_\omegaWω​;
  • w(t)∈Wωw^{(t)}\in W_\omegaw(t)∈Wω​ is an output of Π\PiΠ;
  • the virtual point w(t)+1μ+δ∇ρ(w(t))w^{(t)}+\frac{1}{\mu+\delta}\nabla\rho(w^{(t)})w(t)+μ+δ1​∇ρ(w(t)) lies in WωW_\omegaWω​, the hypothesis of the paper's Theorem 3.2;
  • the MM step is any maximizer of the surrogate.

Theorem 4.2 is stated with rate γ/(μ+δ)\gamma/(\mu+\delta)γ/(μ+δ); the page prints γ/(γ+δ)\gamma/(\gamma+\delta)γ/(γ+δ), which does not match its own proof or Corollary 4.2.

The goal does not assume (F1), (F2), (P1) or the surrogate bound for ρ\rhoρ. Those are milestones about the concrete model. Stating Corollary 4.2 with any of them as a hypothesis, or with Π\PiΠ or the MM step replaced by an abstract map, would be a different and weaker theorem.

A complete development needs, besides the model file, a descent lemma for functions with Lipschitz gradient on a convex set and the variational characterisation of λ2\lambda_2λ2​ of a symmetric matrix. It also needs Gershgorin's theorem and second-order calculus for log-sum-exp functions; these are reusable well beyond this mission. Proofs of any milestone, including the general Lemma 4.1 and Theorem 4.2 independently of the Bradley–Terry model, are welcome.

Selected references

  • M. Vojnović, S.-Y. Yun, K. Zhou, Accelerated MM Algorithms for Ranking Scores Inference from Comparison Data, arXiv:1901.00150v3, 2020 (Operations Research, 2023). https://arxiv.org/abs/1901.00150
  • R. A. Bradley, M. E. Terry, Rank analysis of incomplete block designs I, Biometrika 39, 1952. https://www.jstor.org/stable/2334029
  • D. R. Hunter, MM algorithms for generalized Bradley–Terry models, Ann. Statist. 32, 2004. https://doi.org/10.1214/aos/1079120141
  • F. Caron, A. Doucet, Efficient Bayesian inference for generalized Bradley–Terry models, J. Comput. Graph. Statist. 21, 2012. https://doi.org/10.1080/10618600.2012.638220
  • M. Fiedler, Algebraic connectivity of graphs, Czechoslovak Math. J. 23, 1973. https://doi.org/10.21136/CMJ.1973.101168
  • B. T. Polyak, Gradient methods for minimizing functionals, USSR Comput. Math. Math. Phys. 3, 1963. https://doi.org/10.1016/0041-5553(63)90382-3
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EconomicsOperations Research·Captain: mikedeng1

Informing the Public About a Pandemic: Greater Economic Inequality Makes the Optimal Information Policy Exaggerate Less and Downplay MoreResearch Paper

Motivation

During an epidemic a government knows more about the severity of the disease than the public, and what it chooses to say changes how many people stay at home. Isolation is cheap for some and expensive for others. A person who cannot work from home loses income, and people facing different costs answer the same message in different ways. de Véricourt, Gurkan and Wang (ESMT Working Paper 20-03, 2020; published in Management Science, 2021, doi:10.1287/mnsc.2021.4016) model this as a problem of information design (Bayesian persuasion, Kamenica and Gentzkow 2011). The receivers are a continuum of individuals who play a game among themselves, because each active person raises everyone else's infection risk.

The paper's main finding links economic inequality to misinformation. As the spread of isolation costs grows, the optimal policy exaggerates the severity of the epidemic less often and less strongly, and downplays it more. This mission formalizes that result, Theorem 2, together with the chain of statements on which its proof rests.

Setting

A unit mass of individuals each choose α∈{0,1}\alpha\in\{0,1\}α∈{0,1}: isolate (α=1\alpha=1α=1) or interact (α=0\alpha=0α=0). An isolated individual pays an economic cost ccc, uniformly distributed on C=[θ−σ3,θ+σ3]\mathcal C=[\theta-\sigma\sqrt3,\theta+\sigma\sqrt3]C=[θ−σ3​,θ+σ3​] with mean θ\thetaθ and standard deviation σ\sigmaσ, where θ≥σ3>0\theta\ge\sigma\sqrt3>0θ≥σ3​>0. Write γ=2σ3\gamma=2\sigma\sqrt3γ=2σ3​ for the width of C\mathcal CC. An active individual pays the health risk μPκ\mu P\kappaμPκ. Here μ\muμ is the perceived infectiousness, PPP the mass of active individuals and κ>0\kappa>0κ>0 the healthcare cost of an infection.

A profile a(c,μ)∈{0,1}a(c,\mu)\in\{0,1\}a(c,μ)∈{0,1} is a Bayesian Nash equilibrium (BNE) if, for every μ\muμ and every type ccc, a(c,μ)a(c,\mu)a(c,μ) minimizes αc+(1−α)μPa,μκ\alpha c+(1-\alpha)\mu P_{a,\mu}\kappaαc+(1−α)μPa,μ​κ, where Pa,μ=Ec[1−a(c,μ)]P_{a,\mu}=\mathbb E_c[1-a(c,\mu)]Pa,μ​=Ec​[1−a(c,μ)] is the active population the profile induces.

The infectiousness is ω∈{ωℓ,ωh}\omega\in\{\omega_\ell,\omega_h\}ω∈{ωℓ​,ωh​} with 0<ωℓ<ωh<10<\omega_\ell<\omega_h<10<ωℓ​<ωh​<1; it is high with prior probability ρ∘∈(0,1)\rho^\circ\in(0,1)ρ∘∈(0,1), and the prior mean is μ∘=ρ∘ωh+(1−ρ∘)ωℓ\mu^\circ=\rho^\circ\omega_h+(1-\rho^\circ)\omega_\ellμ∘=ρ∘ωh​+(1−ρ∘)ωℓ​. The paper also assumes ωℓκ≥inf⁡C\omega_\ell\kappa\ge\inf\mathcal Cωℓ​κ≥infC. The government commits to an information policy Γ=(π,M)\Gamma=(\pi,\mathcal M)Γ=(π,M), a law π(m∣ω)\pi(m\mid\omega)π(m∣ω) of messages given the state. Message mmm moves the public to the posterior mean μm\mu_mμm​ by Bayes' rule. For a weight λ∈[0,1]\lambda\in[0,1]λ∈[0,1] on the economy, the government's cost is

Cλ(Γ,a)=λ Ec,m[a(c,μm)c]+(1−λ) Ec,m[(1−a(c,μm))μmPa,μmκ].C_\lambda(\Gamma,a)=\lambda\,\mathbb E_{c,m}[a(c,\mu_m)c]+(1-\lambda)\,\mathbb E_{c,m}[(1-a(c,\mu_m))\mu_mP_{a,\mu_m}\kappa].Cλ​(Γ,a)=λEc,m​[a(c,μm​)c]+(1−λ)Ec,m​[(1−a(c,μm​))μm​Pa,μm​​κ].

An optimal policy minimizes CλC_\lambdaCλ​ over all policies and all their BNE profiles. On the binary message space {mℓ,mh}\{m_\ell,m_h\}{mℓ​,mh​} the paper names four kinds of policy:

  • full disclosure: π(mi∣ωi)=1\pi(m_i\mid\omega_i)=1π(mi​∣ωi​)=1;
  • no disclosure: the message is independent of ω\omegaω;
  • exaggerating: π(mh∣ωh)=1\pi(m_h\mid\omega_h)=1π(mh​∣ωh​)=1 and π(mh∣ωℓ)>0\pi(m_h\mid\omega_\ell)>0π(mh​∣ωℓ​)>0;
  • downplaying: π(mℓ∣ωℓ)=1\pi(m_\ell\mid\omega_\ell)=1π(mℓ​∣ωℓ​)=1 and π(mℓ∣ωh)>0\pi(m_\ell\mid\omega_h)>0π(mℓ​∣ωh​)>0.

In equilibrium (Proposition 1), every type below the threshold c⋆(μ)=μκ(θ+σ3)/(γ+μκ)c^\star(\mu)=\mu\kappa(\theta+\sigma\sqrt3)/(\gamma+\mu\kappa)c⋆(μ)=μκ(θ+σ3​)/(γ+μκ) isolates. The reduced cost at posterior mean μ\muμ is K~λ(μ)\tilde K_\lambda(\mu)K~λ​(μ), and kλk_\lambdakλ​ is its lower convex envelope on [ωℓ,ωh][\omega_\ell,\omega_h][ωℓ​,ωh​]. The functions Gh,Gℓ,G1,G2G_h,G_\ell,G_1,G_2Gh​,Gℓ​,G1​,G2​ of λ\lambdaλ (equations (23)–(25)) define thresholds λ1≤λ2≤12≤λ3≤λ4\lambda_1\le\lambda_2\le\frac12\le\lambda_3\le\lambda_4λ1​≤λ2​≤21​≤λ3​≤λ4​ for the ratio κ/γ\kappa/\gammaκ/γ. Explicit rational functions of the parameters, μλEX\mu^{EX}_\lambdaμλEX​ and μλDP\mu^{DP}_\lambdaμλDP​ ((13)–(16)), are the second posteriors of the optimal exaggerating and downplaying policies.

Formalization targets

Goal: Theorem 2

Let σ<σ′\sigma<\sigma'σ<σ′, every other parameter fixed and admissible at both levels. Then

λi(σ′)≤λi(σ)(i=1,…,4).\lambda_i(\sigma')\le\lambda_i(\sigma)\quad(i=1,\dots,4).λi​(σ′)≤λi​(σ)(i=1,…,4).

When exaggerating is optimal at both levels (λ1<λ<λ2\lambda_1<\lambda<\lambda_2λ1​<λ<λ2​, μ∘<μλEX\mu^\circ<\mu^{EX}_\lambdaμ∘<μλEX​), the exaggeration probabilities of optimal exaggerating policies satisfy

πσ′⋆(mh∣ωℓ)<πσ⋆(mh∣ωℓ).\pi^\star_{\sigma'}(m_h\mid\omega_\ell)<\pi^\star_{\sigma}(m_h\mid\omega_\ell).πσ′⋆​(mh​∣ωℓ​)<πσ⋆​(mh​∣ωℓ​).

When downplaying is optimal at both levels (λ3<λ<λ4\lambda_3<\lambda<\lambda_4λ3​<λ<λ4​, μ∘>μλDP\mu^\circ>\mu^{DP}_\lambdaμ∘>μλDP​), the downplaying probabilities satisfy

πσ⋆(mℓ∣ωh)<πσ′⋆(mℓ∣ωh).\pi^\star_{\sigma}(m_\ell\mid\omega_h)<\pi^\star_{\sigma'}(m_\ell\mid\omega_h).πσ⋆​(mℓ​∣ωh​)<πσ′⋆​(mℓ​∣ωh​).

The probabilities belong to policies that are optimal for the government's problem over all finite-message policies and BNE profiles.

Milestones

  1. Proposition 1, the threshold equilibrium and Pa⋆,μ=c⋆(μ)/(μκ)P_{a^\star,\mu}=c^\star(\mu)/(\mu\kappa)Pa⋆,μ​=c⋆(μ)/(μκ).
  2. The closed form (39) of K~λ\tilde K_\lambdaK~λ​.
  3. Lemma 1, monotonicity and ordering of the GGG's.
  4. Lemma 2, ordering and κ\kappaκ-monotonicity of the λi\lambda_iλi​ and the cutoffs (26).
  5. Lemma 3 A–B, concavity and convexity of K~λ\tilde K_\lambdaK~λ​.
  6. Lemma 3 C–F, a single inflection point and the tangencies at μλDP\mu^{DP}_\lambdaμλDP​ and μλEX\mu^{EX}_\lambdaμλEX​.
  7. Lemma 4, the envelope kλk_\lambdakλ​ in every regime.
  8. The Kamenica–Gentzkow value: the optimal cost equals kλ(μ∘)k_\lambda(\mu^\circ)kλ​(μ∘).
  9. Theorem 1, the optimal policy in every regime.
  10. μλDP\mu^{DP}_\lambdaμλDP​ increasing in γ\gammaγ.
  11. μλEX\mu^{EX}_\lambdaμλEX​ increasing in γ\gammaγ.

Significance

Theorem 2 is the paper's answer to its question. Inequality in the economic cost of isolation pushes the government's message toward downplaying the epidemic, whatever weight the government puts on health. Theorem 1, the full characterization of the optimal policy, is a complete solution of a persuasion problem whose receivers play a congestion-type game, and Theorem 2 is a comparative-statics statement about that solution.

To our knowledge none of these results has a machine-checked proof. The mission produces:

  • a Lean model of persuasion with a nonatomic population of receivers in equilibrium;
  • a formal link from the equilibrium to the reduced convex-envelope problem;
  • the case analysis of Theorem 1;
  • the comparative statics of Theorem 2.

The proofs in the paper are calculus on explicit functions, but they are long and contain sign slips. The proofs of Lemma 3 Parts C and D swap "convex" and "concave". The proof of Theorem 2 attaches the downplaying and exaggerating probabilities to the wrong λ\lambdaλ-intervals. A closed form printed for κ‾0\underline\kappa_0κ​0​ in the proof of Lemma 2 does not equal its definition γG2(0)\gamma G_2(0)γG2​(0). A formal proof settles these points.

Difficulty

The obvious argument goes through the closed forms (17)–(18) of the optimal probabilities and differentiates them in σ\sigmaσ. That argument needs, first, that the optimal policies are those forms. This rests on Theorem 1, the convex-envelope reduction and the curvature analysis of K~λ\tilde K_\lambdaK~λ​. The reduced cost is neither convex nor concave, and its shape changes across seven parameter regimes. Second, the derivatives of μλDP\mu^{DP}_\lambdaμλDP​ and μλEX\mu^{EX}_\lambdaμλEX​ in γ\gammaγ are rational expressions whose signs follow only from the regime bounds κ/γ<G1(λ)\kappa/\gamma<G_1(\lambda)κ/γ<G1​(λ) and κ/γ>G2(λ)\kappa/\gamma>G_2(\lambda)κ/γ>G2​(λ). These bounds involve square roots. Third, the step from the equilibrium game to the reduced problem must handle the indifferent type and arbitrary BNE profiles, not only the threshold profile.

Formalization scope

  • Parameters and standing assumptions. A structure Params holds ωℓ,ωh,ρ∘,θ,σ,κ\omega_\ell,\omega_h,\rho^\circ,\theta,\sigma,\kappaωℓ​,ωh​,ρ∘,θ,σ,κ. The predicate Standing collects the assumptions of §2: 0<ωℓ<ωh<10<\omega_\ell<\omega_h<10<ωℓ​<ωh​<1, 0<ρ∘<10<\rho^\circ<10<ρ∘<1, 0<σ0<\sigma0<σ, σ3≤θ\sigma\sqrt3\le\thetaσ3​≤θ, 0<κ0<\kappa0<κ and ωℓκ≥inf⁡C\omega_\ell\kappa\ge\inf\mathcal Cωℓ​κ≥infC.
  • States and messages. States are Fin 2 (0 =ωℓ=\omega_\ell=ωℓ​). Message spaces are finite types; with a binary state, two messages suffice for the optimum.
  • Zero-probability messages. They get posterior mean ωℓ\omega_\ellωℓ​ and weight 000.
  • Expectations. All values are real numbers. Ec\mathbb E_cEc​ is the uniform average over C\mathcal CC, computed as an interval integral divided by γ\gammaγ.
  • Equilibrium. BNE profiles satisfy the best-response condition for every type in C\mathcal CC and are integrable in ccc.
  • Optimality. Optimal means optimal for (6) with the sender-preferred equilibrium.
  • Reduced costs. KeK_eKe​ and KhK_hKh​ are the integrals (9)–(10). The envelope kλk_\lambdakλ​ is the published definition BiconvexProg.BranchBound.convexEnvelope.
  • Thresholds. λ1,…,λ4\lambda_1,\dots,\lambda_4λ1​,…,λ4​ are written as a supremum or infimum over a regime set with a sentinel value (−1-1−1 or 222) when the set is empty. On [0,1][0,1][0,1] they agree with the paper's max⁡(−ϵ,G−1(κ/γ))\max(-\epsilon,G^{-1}(\kappa/\gamma))max(−ϵ,G−1(κ/γ)).
  • Derivatives. Derivatives in Lemma 3 are taken within [ωℓ,ωh][\omega_\ell,\omega_h][ωℓ​,ωh​].

Theorem 2 must not be stated about the closed forms (17)–(18). It quantifies over policies that are optimal for (6), so a proof has to go through Theorem 1. The government's cost must also not be defined as Em[K~λ(μm)]\mathbb E_m[\tilde K_\lambda(\mu_m)]Em​[K~λ​(μm​)], which would skip Proposition 1. A sorry-free check in the workspace exhibits two parameter pairs (one exaggerating, one downplaying) that satisfy the regime hypotheses of the goal at both inequality levels.

Contributions to every milestone are welcome. The general pieces are reusable beyond this paper:

  • the Kamenica–Gentzkow reduction for a binary state and finite messages;
  • convex envelopes of one-dimensional functions with a single inflection point.

Selected references

  • F. de Véricourt, H. Gurkan, S. Wang, Informing the Public About a Pandemic, ESMT Working Paper 20-03, 2020; Management Science 67(10), 2021. https://doi.org/10.1287/mnsc.2021.4016
  • E. Kamenica, M. Gentzkow, Bayesian Persuasion, American Economic Review 101(6), 2011. https://doi.org/10.1257/aer.101.6.2590
  • F. A. Al-Khayyal, J. E. Falk, Jointly Constrained Biconvex Programming, Mathematics of Operations Research 8(2), 1983 (the convex-envelope definition reused here). https://doi.org/10.1287/moor.8.2.273
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EconomicsOperations Research·Captain: mikedeng1

Market Freeze and Bank Capital Structure Heterogeneity: With Interbank Loan Trading, the Unique Equilibrium Is Heterogeneous Exactly for Intermediate Boom ProbabilitiesResearch Paper

Why loan trading can change bank capital

Banks that can sell loans after origination may face different incentives to screen them before lending. A buyer that has invested in screening can inspect a seller's loan and buy it when its quality is high. That opportunity can make screening more valuable and reduce the equity a buyer needs to commit. At the same time, a seller may prefer to avoid the screening cost and rely on a later sale. Song and Thakor study when these two choices coexist in an interbank market, even though banks begin with the same opportunities and information (Song and Thakor, SSRN 3667175). The resulting question concerns the capital structure of banks and whether a trading market opens a region of heterogeneous behavior between two homogeneous regimes.

The paper's Proposition 2 is a result about this transition as the chance of a boom changes. It also compares the width of the heterogeneous region across market efficiencies. The mission formalizes that result from the authors' specified model and their preprint's assumptions. The preprint describes the paper as forthcoming in Management Science; the DOI record identifies the associated journal work.

The model and its quantities

A good loan pays X>IX>IX>I at its final date. A medium loan pays XXX in a boom and zero in a recession. Both require an initial investment III. The probability of a boom is θ∈[0,θˉ]\theta\in[0,\bar\theta]θ∈[0,θˉ], with θˉ<I/X\bar\theta<I/Xθˉ<I/X, so a medium loan is not creditworthy on its own. Before a bank screens, each type has probability one half. Screening costs ccc and reveals the type. A bank can finance the loan with deposits and equity; supplying one unit of equity costs insiders ψ\psiψ per unit. Default also loses the bank its charter value Y(θ)Y(\theta)Y(θ). The paper restricts X,I,c,δ,ψ,θˉX,I,c,\delta,\psi,\bar\thetaX,I,c,δ,ψ,θˉ, and YYY by Assumptions 1–4 and fixes the matching technology by Assumption 5 (preprint, pp. 7–12); YYY is increasing and concave.

Without loan trading, the minimum screening equity is Ehom(θ)E^{\mathrm{hom}}(\theta)Ehom(θ), the profit from screening is πshom(θ)\pi_s^{\mathrm{hom}}(\theta)πshom​(θ), and the profit without screening is πnshom(θ)\pi_{ns}^{\mathrm{hom}}(\theta)πnshom​(θ). Their difference, Δπhom(θ)\Delta\pi^{\mathrm{hom}}(\theta)Δπhom(θ), is the screening advantage. The paper writes each quantity as an explicit real-valued function of θ\thetaθ in equations (8)–(11). A cutoff θ∗\theta^*θ∗ separates the choices when the loan market is closed (Proposition 1, p. 15).

With trading, some banks can be buyers that screen, while others are sellers that do not. If buyers have mass NbN_bNb​ and sellers mass NsN_sNs​, market tightness is n=Nb/Nsn=N_b/N_sn=Nb​/Ns​. A seller meets a buyer with probability α(n)=λn/(1+n)\alpha(n)=\lambda n/(1+n)α(n)=λn/(1+n); a buyer meets a seller with probability λ/(1+n)\lambda/(1+n)λ/(1+n). Here λ∈[0,1]\lambda\in[0,1]λ∈[0,1] measures matching efficiency. The buyer's bargaining weight is 1/(1+n)1/(1+n)1/(1+n), and the price for a verified good loan is p(n)=X−(X−I)/(1+n)p(n)=X-(X-I)/(1+n)p(n)=X−(X−I)/(1+n). Trading reduces the buyer's required equity to Ehet(θ,n)=Ehom(θ)−λ(X−p(n))/(1+n)E^{\mathrm{het}}(\theta,n)=E^{\mathrm{hom}}(\theta)-\lambda(X-p(n))/(1+n)Ehet(θ,n)=Ehom(θ)−λ(X−p(n))/(1+n) (Assumption 5, equation (13), and Lemma 1; the matching function follows Kiyotaki and Wright (1993)).

Formalization targets

The main target is Proposition 2, p. 21. Under the paper's assumptions and its endpoint conditions, there are cutoffs 0<θL<θH<θˉ0<\theta_L<\theta_H<\bar\theta0<θL​<θH​<θˉ. Every bank screens below θL\theta_LθL​; none screens above θH\theta_HθH​; between them, buyers and sellers coexist. In the interior the buyer/seller ratio is determined by

λ(X−I)[1−θ2n−1n+1−ψ(n+1)2]=Δπhom(θ).\lambda(X-I)\left[\frac{1-\theta}{2}\frac{n-1}{n+1}-\frac{\psi}{(n+1)^2}\right] =\Delta\pi^{\mathrm{hom}}(\theta).λ(X−I)[21−θ​n+1n−1​−(n+1)2ψ​]=Δπhom(θ).

The two cutoffs solve the paper's equations (A4) and (A7). The mission also targets uniqueness of the equilibrium in every regime, expansion of the heterogeneous region when a larger feasible λ\lambdaλ is used, and falling nnn and p(n)p(n)p(n) as θ\thetaθ rises within that region. The milestone list covers the matching identities of Assumption 5, the Nash price (13), Lemma 1's equity threshold, the monotonicity of EhomE^{\mathrm{hom}}Ehom (footnote 19), the sign form of the cost condition (A1), the strict concavity of Δπhom\Delta\pi^{\mathrm{hom}}Δπhom, the closed-market cutoff of Proposition 1, the two trading cutoffs (A4) and (A7), the interior indifference equation (A9)/(15), and the monotonicity in nnn of the left side of (15) (Appendix A, pp. 34–37).

What the result establishes

The result identifies a region in which banks that started alike choose different capital structures and screening decisions. A loan-trading market changes the relative payoffs of screening and not screening, and the boom probability determines which choice can survive a unilateral switch. The cutoffs show precisely where the market moves from all-screening to mixed behavior and then to no-screening. The market-efficiency comparison says when the mixed region widens. These distinctions matter for the paper's subsequent welfare comparison and its discussion of capital requirements (Song and Thakor, §§3–4).

The result is proved in the source paper. The remaining work is a machine-checked proof of the model-specific statements and their consequences, including the bargaining maximum, incentive threshold, cutoff existence and uniqueness, and comparative statics. The definitions are reusable for further formal work on the paper's welfare and capital-requirement results; this mission does not assert that those extensions have been formalized.

Main mathematical difficulty

The equilibrium claim joins several regimes in one statement. The homogeneous corners are governed by whether a single bank would gain by changing its behavior, whereas the interior is governed by equality of buyer and seller profits. A root of the displayed equation alone does not establish an equilibrium: the cutoff and no-switch conditions must also hold, and the root must be unique. Moreover, the source's claimed global negative derivative for Δπhom\Delta\pi^{\mathrm{hom}}Δπhom is not implied by its assumptions. The cutoff argument must therefore use a valid shape condition without importing that false assertion. The charter-value function YYY is concave but otherwise general, so reasoning cannot rely on a particular polynomial example.

Formalization scope

Lean represents all expectations by the closed-form real expressions in equations (7)–(15); there is no probability space. The parameter structure fixes X,I,c,δ,ψ,λ,θˉX,I,c,\delta,\psi,\lambda,\bar\thetaX,I,c,δ,ψ,λ,θˉ, and YYY. All five numbered assumptions remain explicit, including Assumption 4. The formalization reads screening cost and equity cost as positive, reads the paper's smooth YYY as differentiable on [0,θˉ][0,\bar\theta][0,θˉ], and requires λ>0\lambda>0λ>0 for an open market. The bargaining price is optimized over [I,X][I,X][I,X]. The buyer meeting probability uses its continuous value λ\lambdaλ at n=0n=0n=0. Proposition 1 uses a reduced closed-market outcome that records screening and equity; at its profit tie, footnote 21 selects no screening. The open-market equilibrium variable is the buyer share s∈[0,1]s\in[0,1]s∈[0,1], with n=s/(1−s)n=s/(1-s)n=s/(1−s) only in the interior; the all-buyer corner uses the sole-seller limit instead. Price and buyer equity are constructed from the paper's equations, and are never arbitrary choices. The cutoffs are required to satisfy 0<θL<θH<θˉ0<\theta_L<\theta_H<\bar\theta0<θL​<θH​<θˉ, so all three regimes are nonempty; a version in which the equilibrium is any root of (15), or in which price or buyer equity are free variables, would be a different and weaker statement and is excluded. The hypotheses are jointly satisfiable, but only for small market efficiency (numerical searches find λ≲0.015\lambda\lesssim0.015λ≲0.015); an explicit rational instance is checked in Lean.

The preprint prints a plus sign in (A6) where its preceding deviation inequality requires a minus sign; the Lean condition uses the latter. The paper also claims that the absolute sensitivity of nnn to θ\thetaθ falls with λ\lambdaλ, but that claim is false under its hypotheses, so the mission does not include either sensitivity clause of Proposition 2. The paper's unsupported global first-derivative bound for Δπhom\Delta\pi^{\mathrm{hom}}Δπhom is excluded. The milestone from the proof of Proposition 5 states its displayed second-derivative identity wherever Y′′Y''Y′′ exists, and states strict concavity throughout the interval. Any further result should keep these corrections explicit. Contributions to the bargaining, real-analysis, and equilibrium lemmas are welcome; proofs of the milestone statements can then support the capstone theorem.

Selected references

  • N. Kiyotaki and R. Wright, A search-theoretic approach to monetary economics, American Economic Review 83(1), 63–77, 1993. JSTOR
  • F. Song and A. V. Thakor, Market Freeze and Bank Capital Structure Heterogeneity, SSRN preprint 3667175, version dated 2022-02-21; forthcoming in Management Science in the source artifact. SSRN; DOI.
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EconomicsOperations Research·Captain: mikedeng1

That’s Not Fair: Tariff Structures for Electric Utilities with Rooftop Solar: A Tiered Solar-Discriminating Tariff Induces Any Target Adoption Outcome Without Cross-Subsidization When Customers GainResearch Paper

Motivation

Rooftop solar changes both a household's electricity bill and the utility's cost of serving its customers. A tariff that encourages an aggregate amount of solar generation can still leave one customer tier paying more than before. Regulators therefore face a joint design question: can they induce a chosen adoption pattern while meeting the solar supplier's and utility's profit requirements and protecting every customer tier? Singh and Scheller-Wolf formulate this question for a solar company that sells generation through a power purchase agreement, a regulated utility, and households grouped into tiers. Their SSRN paper studies several tariff families; Proposition 5 identifies a tiered tariff that can implement the selected outcome and, when the customers' aggregate financial gain is nonnegative, avoid cross-subsidization.

The selected outcome is assumed to have been chosen for social welfare reasons. The result concerns the next task: implementing it through the tariff while customers decide whether to adopt and the solar company chooses its price. That distinction matters because a tariff that appears to allocate enough money to all parties may change the solar company's preferred price, and therefore change which households adopt.

Setting

There are finitely many customer tiers iii. Tier iii contains hih_ihi​ households. Each household has annual electricity demand did_idi​, potential solar generation gig_igi​, and excess generation eie_iei​. If it adopts solar, it draws di′=di−(gi−ei)d'_i=d_i-(g_i-e_i)di′​=di​−(gi​−ei​) from the grid and sells eie_iei​ back. The target adopting set AAA identifies the tiers whose households install solar. Let E0=∑ihidiE^0=\sum_i h_i d_iE0=∑i​hi​di​ be baseline utility demand, ΔEA=∑i∈Ahigi\Delta_E^A=\sum_{i\in A}h_i g_iΔEA​=∑i∈A​hi​gi​ the target rooftop generation, and EA=E0−ΔEAE^A=E^0-\Delta_E^AEA=E0−ΔEA​ net utility demand. The paper restricts attention to outcomes with at least one adopting tier and ΔEA≤E0\Delta_E^A\le E^0ΔEA​≤E0 (§3, pp. 10–11).

The regulator sets a tariff T(d′,e,s)T(d',e,s)T(d′,e,s), a customer's utility bill based on grid draw d′d'd′, electricity sold to the grid eee, and adoption indicator sss. For tier iii, the two relevant bills are T(di,0,0)T(d_i,0,0)T(di​,0,0) and T(di′,ei,1)T(d'_i,e_i,1)T(di′​,ei​,1). A solar company chooses a single price psp_sps​ per unit generated by adopting households and pays unit cost cs(y)c_s(y)cs​(y) when its sales volume is yyy. Each customer adopts when its adopter bill plus psgip_sg_ips​gi​ is no larger than its nonadopter bill. With ties favoring adoption, this is ps≤t(i)p_s\le t(i)ps​≤t(i), where t(i)=[T(di,0,0)−T(di′,ei,1)]/git(i)=[T(d_i,0,0)-T(d'_i,e_i,1)]/g_it(i)=[T(di​,0,0)−T(di′​,ei​,1)]/gi​. Thus the solar company's price determines both its sales volume and its unit cost (§§3–4, pp. 10–13).

The regulator's P2 objective is the largest increase in a tier household's cash outflow relative to the baseline rate pr0p_{r0}pr0​. A nonpositive objective means no tier is financially worse off, which the paper calls cross-subsidization free. P2 also requires a specified solar-company profit ΔS\Delta_SΔS​ and utility profit change ΔU\Delta_UΔU​. Write ΔWF\Delta_{WF}ΔWF​ for the financial welfare improvement of the whole system and ΔC=ΔWF−ΔS−ΔU\Delta_C=\Delta_{WF}-\Delta_S-\Delta_UΔC​=ΔWF​−ΔS​−ΔU​ for customers' aggregate financial gain (§4, pp. 12–15).

Formalization targets

Proposition 5(a): inducing the target outcome

Tariffs of type T3T_3T3​ charge nonadopters prdip_rd_ipr​di​ and adopters prdi′−prei+fip_rd'_i-p_re_i+f_ipr​di′​−pr​ei​+fi​, where prp_rpr​ is a common rate and fif_ifi​ a tier-specific adopter charge. The paper constructs one such tariff, T∗T^*T∗, from the target outcome. At its prescribed price t(m)t(m)t(m), the target tiers adopt, the solar company earns ΔS\Delta_SΔS​ and earns strictly less at every other price, and the utility receives its specified profit change ΔU\Delta_UΔU​:

A(t(m))=A,ΠS(t(m))=ΔS>ΠS(p)(p≠t(m)),ΔΠU=ΔU.A(t(m))=A,\qquad \Pi_S(t(m))=\Delta_S>\Pi_S(p)\quad(p\ne t(m)),\qquad \Delta\Pi_U=\Delta_U.A(t(m))=A,ΠS​(t(m))=ΔS​>ΠS​(p)(p=t(m)),ΔΠU​=ΔU​.

This is the feasibility claim of Proposition 5(a), p. 18.

Proposition 5(b): equity and optimality

When the aggregate customer gain is nonnegative, T∗T^*T∗ has a nonpositive P2 objective:

ΔC≥0⟹max⁡iΔoutflowi(T∗,t(m))≤0.\Delta_C\ge0\quad\Longrightarrow\quad\max_i\Delta\mathrm{outflow}_i(T^*,t(m))\le0.ΔC​≥0⟹imax​Δoutflowi​(T∗,t(m))≤0.

If a tier with the smallest demand does not adopt, Proposition 5(b) further says T∗T^*T∗ minimizes this objective among feasible T3T_3T3​ tariffs. Both clauses belong to the combined goal theorem. The milestone list also includes the customer threshold, the welfare identity, the T3T_3T3​ threshold formula, Proposition 5(a), Lemma 1, the retail-rate identity for T∗T^*T∗, and the cross-subsidization clause (p. 18 and proof on p. S.3).

Significance

Proposition 5 gives a tariff implementation for any admissible target adoption set without relying on control of the solar company's price. Its equity guarantee has a clear limit: it requires nonnegative aggregate customer gain. Within the paper's T3T_3T3​ family, the additional lowest-demand condition gives an exact minimax result for customers' bill changes (Proposition 5, p. 18). This distinguishes the existence of an implementing tariff from its distributional performance.

The mathematical result is already proved in the paper; this mission asks for a machine-checked development of its model, construction, and claims. The reusable pieces include finite-tier induced-adoption sets, price-dependent sales volume, and the accounting identities between company profits and customer outflows. The statements in this proposal are proof targets and do not claim an existing Lean proof.

Difficulty

Setting each customer's adoption threshold to produce AAA is insufficient by itself. The solar company chooses psp_sps​ to maximize profit, and a change in price can change both the adopting set and the unit cost cs(y)c_s(y)cs​(y). The prescribed price must beat every alternative real price strictly. The utility's required profit change constrains the same tier fees used to set thresholds. Finally, a nonnegative total customer gain does not by itself imply that every tier benefits; P2 asks about the largest individual tier increase. These coupled requirements are visible in the paper's P2 formulation and in the proof of Proposition 5 (pp. 13–14, 18, S.3).

Formalization scope

Lean represents tiers by a finite type and outcomes by finite sets of tiers. All demands, prices, bills, costs, volumes, and profit changes are real. The tier type is unordered: the paper relabels tiers during T∗T^*T∗'s construction. A tariff is represented by its two bills per tier, the evaluations P2 uses. For T3T_3T3​, fees are indexed by tier, consistent with the paper's statement that the utility can infer a solar customer's tier from grid draw (p. 17). Adoption ties go to adoption, and the solar company's price ranges over all real numbers. P2 feasibility includes the induced adopter set, the firm's unique best response, and the utility constraint.

The standing assumptions state hi,di,gi>0h_i,d_i,g_i>0hi​,di​,gi​>0, 0≤ei≤gi0\le e_i\le g_i0≤ei​≤gi​, nonincreasing csc_scs​, and ΔS>0\Delta_S>0ΔS​>0. Positivity of hi,di,gih_i,d_i,g_ihi​,di​,gi​ is implicit in the paper and makes the displayed volume and price divisions valid. The target set is nonempty and satisfies ΔEA≤E0\Delta_E^A\le E^0ΔEA​≤E0. The utility's total generation cost is outside the household sum in its accounting constraint; this is the reading consistent with the paper's welfare identity. The printed indexing slips in (17) and (19) are avoided by expressing the induced equilibrium directly. Customer aggregate gain is computed from ΔWF−ΔS−ΔU\Delta_{WF}-\Delta_S-\Delta_UΔWF​−ΔS​−ΔU​, rather than defined from the desired conclusion. The optimality quantifier covers feasible T3T_3T3​ tariffs, the family studied in §4.3. Contributions may develop the equilibrium argument, the accounting lemmas, the T∗T^*T∗ rate identity, or the complete optimality proof.

Selected references

  • Singh, S. P., and A. Scheller-Wolf, That’s Not Fair: Tariff Structures for Electric Utilities with Rooftop Solar, SSRN version, 2022. SSRN 2926676. Source for all statement and appendix page references in this mission.
  • Singh, S. P., and A. Scheller-Wolf, That’s Not Fair: Tariff Structures for Electric Utilities with Rooftop Solar, Manufacturing & Service Operations Management 24(3), 2022. DOI:10.1287/msom.2020.0930. Published bibliographic record; the mission cites the SSRN version's numbering and pages.
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EconomicsOperations Research·Captain: mikedeng1

Essentiality Checks for Standard Essential Patents: Without an Effective FRAND Royalty Cap, a Marginal Increase in the Accuracy of Essentiality Checks Reduces WelfareResearch Paper

Motivation

A standard-essential patent is a patent that an implementer must use to make a product compliant with a technical standard. Its owner may demand a royalty from firms using the standard. Whether a patent is truly essential can be disputed, yet licensing offers and investment decisions are made before a court resolves that dispute. Standard-setting organizations can commission essentiality checks that certify patents before licensing. Better checks identify more patents that are not essential, but they also change what an implementer believes about a patent that passes the check. Schuett and Wipusanawan study how those two effects interact with litigation and research investment in their TILEC discussion paper, §§2–5.

A common policy intuition is that a more accurate check should save litigation costs by excluding weak patent claims. The paper identifies a countervailing effect in a model where an innovator chooses research effort before it knows whether its patent will be essential. The question here is local: when a small increase in check accuracy leaves each state's licensing regime unchanged, how does equilibrium welfare change if the patent owner faces no effective cap on royalties? The paper's Proposition 1 answers this question, building on its licensing, investment, and welfare formulas Schuett and Wipusanawan, pp. 16–25.

Setting

An upstream firm chooses research effort x∈[0,1]x\in[0,1]x∈[0,1] at cost c(x)c(x)c(x). Research succeeds with probability xxx. Following success, the standard uses the firm's technology, its patent is essential, and the commercial value is one of finitely many values viv_ivi​ with probabilities piHp_i^HpiH​. Following failure, the standard uses a status-quo technology, the patent is not essential, and value viv_ivi​ occurs with probability pi0p_i^0pi0​. The separate distribution pLp^LpL for the unsuccessful upstream technology enters the paper's assumption that the status quo has higher expected value than that technology. The model requires ∑ipiHvi>∑ipi0vi>∑ipiLvi\sum_i p_i^H v_i>\sum_i p_i^0 v_i>\sum_i p_i^L v_i∑i​piH​vi​>∑i​pi0​vi​>∑i​piL​vi​ Assumption 1, p. 10.

An essentiality check certifies an essential patent correctly. It also certifies a non-essential patent in error with probability 1−β1-\beta1−β, where β∈[0,1]\beta\in[0,1]β∈[0,1] is accuracy. After observing certification and value, the upstream firm offers a royalty fraction αi\alpha_iαi​ bounded by αˉ∈(0,1]\bar\alpha\in(0,1]αˉ∈(0,1]. The downstream firm can accept or litigate. Litigation costs each firm lil_ili​; the court determines essentiality correctly. A non-certified patent earns the upstream firm no licensing revenue in this model. The paper assumes li<αˉvil_i<\bar\alpha v_ili​<αˉvi​ Assumption 2, p. 12.

A certified patent can produce a hybrid licensing outcome, in which the unsuccessful firm sometimes offers a low royalty and the downstream firm sometimes litigates a high offer, or a pooling outcome, in which both types offer the maximum royalty. Write HHH and PPP for the sets of states with those outcomes. The implementer's belief that a certified patent is essential, λic\lambda_i^cλic​, depends on expected effort x^\hat xx^, accuracy β\betaβ, and the value distributions. In equilibrium, x^=x∗\hat x=x^*x^=x∗. The paper derives a private investment wedge from the difference between expected licensing revenues after success and failure, and a social wedge from expected value less both parties' litigation costs equations (1)–(7), pp. 16–22.

Formalization targets

The main target is Proposition 1. With an ineffective royalty cap, αˉ=1\bar\alpha=1αˉ=1, fix β0<1\beta_0<1β0​<1 where no positive-probability state lies exactly at the hybrid–pooling boundary. Along a continuous path of nearby equilibrium efforts x∗(β)x^*(\beta)x∗(β), the right derivative of welfare www satisfies

ddβw(β,x∗(β))∣β0+≤0.\frac{d}{d\beta}w\bigl(\beta,x^*(\beta)\bigr)\bigg|_{\beta_0+}\le 0.dβd​w(β,x∗(β))​β0​+​≤0.

The inequality is weak because the paper concludes ∂w∗/∂β≤0\partial w^*/\partial\beta\le0∂w∗/∂β≤0 Proposition 1 and its proof, pp. 24–25. The target concerns a marginal increase that preserves the licensing regimes; it makes no claim about a large change that moves states between HHH and PPP.

The milestone statements cover the regime condition (4), the private revenue wedge (5), the welfare identity (6), Lemma 2's positive response of research effort to accuracy, and Lemma 3's comparison of private and social investment incentives. Their order exposes the quantities the goal uses without replacing Proposition 1 with a narrower fixed-regime statement.

Significance

Within this model, the result says that improved screening can lower welfare when unconstrained licensing already induces too much research investment. It identifies a limit on an intervention aimed at reducing disputes over essentiality: even a check that detects more non-essential patents may change the incentives of firms whose patents pass. This is a statement about the model's local equilibrium, not a claim that every real-world checking program lowers welfare. The paper separately examines changes large enough to alter licensing regimes and the case of an effective royalty cap Schuett and Wipusanawan, §§5–6.

The economic theorem is proved in the cited paper. This mission asks for a machine-checked account of its finite-state model and the local welfare claim; the displayed Lean statements are open proof targets. The shared definitions of certification beliefs, licensing outcomes, revenue, and welfare are useful for checking later variants of the model, including alternative certification errors or royalty caps. No machine-checked proof of this paper's proposition is claimed here.

Difficulty

The local comparison crosses three choices. Accuracy changes the chance that a failed innovator is certified. Certification changes the downstream firm's belief when it sees a high royalty. The resulting licensing outcome affects the innovator's incentive to invest, and effort feeds back into the belief. Simply holding effort fixed misses the welfare effect in Proposition 1. Treating the hybrid and pooling sets as fixed for all accuracy levels is also too broad: the paper restricts the result to a neighborhood where the regime condition does not meet equality. At a boundary, the relevant formulas can switch and the local derivative need not have the same form pp. 20, 24–25.

Formalization scope

The Lean model uses real values and probabilities on a finite state type Fin n. Each of pHp^HpH, pLp^LpL, and p0p^0p0 is a nonnegative probability vector. Assumptions 1 and 2, 0<αˉ≤10<\bar\alpha\le10<αˉ≤1, and the paper's increasing convex research cost with c′(0)=0c'(0)=0c′(0)=0 and c′(x)→∞c'(x)\to\inftyc′(x)→∞ as x↑1x\uparrow1x↑1 are explicit standing conditions. The cost is represented by a real function twice continuously differentiable on (−∞,1)(-\infty,1)(−∞,1), which covers the effort domain below one. Equilibrium effort is interior and satisfies the private first-order condition with the implementer's belief equal to effort.

Three premises used in the paper's argument are made explicit. Litigation costs satisfy li>0l_i>0li​>0. The second derivative at the equilibrium effort satisfies c′′(x∗)>0c''(x^*)>0c′′(x∗)>0, as required by the displayed denominator in Lemma 2; convexity alone gives only nonnegativity. A right-continuous equilibrium-effort path supplies nearby equilibria for the local comparison. The derivative is one-sided because the target concerns an increase from β0\beta_0β0​, including β0=0\beta_0=0β0​=0. Strictness of the regime condition is demanded only for states with positive probability under pHp^HpH or p0p^0p0; an absent state cannot affect welfare or investment.

The belief formula is the paper's ratio when its denominator is positive. Its value at a zero-probability state is immaterial to the weighted outcome; the regime milestone also gives a cross-multiplied condition there. Uncertified patents give the upstream firm zero revenue, and the downstream firm retains value without litigation. Welfare is assembled from the two firms' payoffs in every certification and licensing outcome, then related to equation (6). Defining welfare directly by (6), fixing HHH in the goal, or assuming the derivative of x∗x^*x∗ would remove the main work of the proposition. Contributions to the finite-state payoff model, the regime and welfare identities, and the local derivative and wedge comparison are all within scope.

Selected references

  • F. Schuett and C. Wipusanawan, Essentiality Checks for Standard Essential Patents, TILEC Discussion Paper DP 2023-21, December 2023, SSRN 4688864. The pinned discussion-paper version is the citation basis for every page and equation in this mission.
  • F. Schuett and C. Wipusanawan, Essentiality Checks for Standard Essential Patents, Management Science, 2024, DOI 10.1287/mnsc.2023.04292. The mission does not use the journal pagination.
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Convex OptimizationOperations ResearchOptimization·Captain: mikedeng1

A Unified Analysis of a Class of Proximal Bundle Methods for Solving Hybrid Convex Composite Optimization Problems: An Iteration-Complexity Bound for Every GPB VariantResearch Paper

Motivation

Bundle methods minimize a convex objective while using local supporting affine functions to represent a component that may be nonsmooth. Their iterations can spend time improving the model without moving the current proximal center, so a bound on useful center changes alone does not bound the total work. Liang and Monteiro study a common generic proximal bundle (GPB) framework for several model update rules and give one explicit iteration bound that covers every rule admitted by its bundle update blackbox. The result is a proved theorem in their paper, rather than an open complexity conjecture.

The framework matters when a convex objective combines a component supplied through subgradients with another component whose proximal subproblems can be handled directly. One-cut, two-cut, and multiple-cut bundle updates fit the same abstract requirements in the paper. A common statement makes their guarantees comparable without identifying a specific update formula as canonical.

Setting

The problem is to minimize hybrid convex composite objective ϕ=f+h\phi=f+hϕ=f+h over Rn\mathbb R^nRn. The effective domain D=dom⁡hD=\operatorname{dom}hD=domh is nonempty and contained in the domain of fff. The function hhh is lower semicontinuous and μ\muμ-convex, for μ≥0\mu\ge0μ≥0: its convexity inequality gains the quadratic term μα(1−α)∥x−y∥2/2\mu\alpha(1-\alpha)\|x-y\|^2/2μα(1−α)∥x−y∥2/2. For each x∈Dx\in Dx∈D, a chosen subgradient f′(x)f'(x)f′(x) defines a supporting affine cut

ℓf(u;x)=f(x)+⟨f′(x),u−x⟩.\ell_f(u;x)=f(x)+\langle f'(x),u-x\rangle.ℓf​(u;x)=f(x)+⟨f′(x),u−x⟩.

The hybrid oracle condition allows both a constant and a distance-dependent part:

∥f′(x)−f′(y)∥≤2Mf+Lf∥x−y∥(x,y∈D),\|f'(x)-f'(y)\|\le 2M_f+L_f\|x-y\|\qquad(x,y\in D),∥f′(x)−f′(y)∥≤2Mf​+Lf​∥x−y∥(x,y∈D),

where Mf,Lf≥0M_f,L_f\ge0Mf​,Lf​≥0. For tolerance εˉ>0\bar\varepsilon>0εˉ>0, the pair (Mˉf,Lˉf)(\bar M_f,\bar L_f)(Mˉf​,Lˉf​) minimizes M2+εˉLM^2+\bar\varepsilon LM2+εˉL among all nonnegative pairs satisfying the same condition. An optimal point x0∗x_0^*x0∗​ nearest the initial point x0∈Dx_0\in Dx0​∈D exists under the paper's assumptions, and d0=∥x0−x0∗∥d_0=\|x_0-x_0^*\|d0​=∥x0​−x0∗​∥.

A GPB run is an infinite sequence of points xjx_jxj​, best-so-far points yjy_jyj​, centers xjcx_j^cxjc​, and convex bundle models Γj\Gamma_jΓj​. At a serious update, the next center is the current point and the next model lies between ℓf(⋅;xj)+h\ell_f(\cdot;x_j)+hℓf​(⋅;xj​)+h and ϕ\phiϕ. At a null update, the center stays fixed and a bundle update blackbox selects the next model. Its output must dominate a mixture of a fresh cut and an auxiliary model Γˉj\bar\Gamma_jΓˉj​ that agrees with the previous model at xjx_jxj​ and has xjx_jxj​ as its proximal minimizer. Every new xjx_jxj​ minimizes its model plus the squared distance to its center divided by 2λ2\lambda2λ. The best-so-far point yjy_jyj​ minimizes the observed objective values. The gap tjt_jtj​ compares ϕ(yj)\phi(y_j)ϕ(yj​) with the proximal model value; a step is serious when tj≤εˉ/2t_j\le\bar\varepsilon/2tj​≤εˉ/2.

Formalization targets

The goal is Proposition 4.9, an explicit total iteration bound for every run admitted by GPB when τ\tauτ is set by equation (38). Put λμ=λ/(1+λμ)\lambda_\mu=\lambda/(1+\lambda\mu)λμ​=λ/(1+λμ) and

tˉ=Mˉf2+4(Lˉf+2)(max⁡{1,2λLˉf}d0+λMˉf)2.\bar t=\bar M_f^2+4(\bar L_f+2) \bigl(\max\{1,2\lambda\bar L_f\}d_0+\lambda\bar M_f\bigr)^2.tˉ=Mˉf2​+4(Lˉf​+2)(max{1,2λLˉf​}d0​+λMˉf​)2.

There is an index jjj with ϕ(yj)−ϕ∗≤εˉ\phi(y_j)-\phi^*\le\bar\varepsilonϕ(yj​)−ϕ∗≤εˉ and

j≤(⌈(1+8λμ(Mf2+εˉLf)εˉ)max⁡{log⁡4tˉεˉ,0}⌉+1)(serBound⁡(μ,λ,εˉ,d02)+1).j\le\left( \left\lceil\left(1+\frac{8\lambda_\mu(M_f^2+\bar\varepsilon L_f)}{\bar\varepsilon}\right) \max\left\{\log\frac{4\bar t}{\bar\varepsilon},0\right\}\right\rceil+1\right) \left(\operatorname{serBound}(\mu,\lambda,\bar\varepsilon,d_0^2)+1\right).j≤(⌈(1+εˉ8λμ​(Mf2​+εˉLf​)​)max{logεˉ4tˉ​,0}⌉+1)(serBound(μ,λ,εˉ,d02​)+1).

Here serBound⁡\operatorname{serBound}serBound is the minimum of the two serious-iteration expressions in (61), with the paper's limiting convention at μ=0\mu=0μ=0. The milestones follow the two quantities in this product: Corollary B.2 and Lemma 4.2 yield the serious-iteration estimate; Proposition 4.3 packages it. Equation (7), Lemmas 4.6, A.3, and 4.7 bound the behavior within each cycle; Proposition 4.8 bounds the cycle length. The goal combines the two bounds without selecting one concrete bundle update.

Significance

The theorem gives a finite tolerance certificate with a numerical bound on all iterations, including those that only improve the bundle model. The bound depends on the oracle parameters, curvature, initial distance to the solution set, tolerance, and proximal stepsize. It therefore states what an implementation gains by satisfying the BU conditions even when its internal model construction differs from another implementation. The broader paper also analyzes particular update schemes and an adaptive method, but the target here is the common GPB result Liang and Monteiro, §3–4.

The mathematical result is already proved in the source. This mission asks for machine-checked definitions and proofs of its explicit bound and the selected supporting statements. No machine-checked proof is supplied by these open theorem items. The definitions of the hybrid oracle, proximal model, and abstract GPB run can be reused to formalize the paper's concrete update schemes later.

Difficulty

Counting serious steps does not count intervening null steps. A null step can leave the center fixed while the model changes, and the BU condition permits many such models. The main obstacle is to obtain a uniform bound for a complete cycle from conditions that are local to one model update. The separate analytic obstacle is the hybrid descent estimate (7): the oracle bound contains both a constant term and a term proportional to distance, and the needed quadratic coefficient is Lf/2L_f/2Lf​/2, not the easier LfL_fLf​. The source's auxiliary proximal displacement estimate also depends on lower semicontinuity so that its minimizers exist.

Formalization scope

The Lean space is EuclideanSpace ℝ (Fin n), with its usual norm and real inner product. The function domain DDD stands for dom⁡h\operatorname{dom}hdomh; fff, hhh, and each bundle model are real-valued on DDD, with an extended value +∞+\infty+∞ off DDD when lower semicontinuity is stated. All model inequalities and proximal minimizations are over DDD. This represents the paper's extended-valued functions without ambiguous arithmetic at +∞+\infty+∞. The selected subgradient inequality is also required only on DDD. The source's lower semicontinuity of fff and of the BU auxiliary model is omitted, which strengthens the resulting claims; lower semicontinuity of hhh and of each generated model remains. The abstract serious-iterate sequences explicitly keep their auxiliary points in DDD.

Index zero is initialization and counts as serious because t0=0t_0=0t0​=0; subsequent indices are natural numbers. The GPB run predicate retains the existential auxiliary model in every null update, so it covers every admissible variant. The goal concludes existence of a successful bounded index. It assumes Mf2+εˉLf>0M_f^2+\bar\varepsilon L_f>0Mf2​+εˉLf​>0 so equation (38) defines τ∈(0,1)\tau\in(0,1)τ∈(0,1). For μ=0\mu=0μ=0, the serious-step formula uses the limiting value rather than real division by zero. The printed cycle and total bounds omit an integer rounding and can be too small; the formal targets use a ceiling and a nonnegative logarithm. Lemma 4.2(c), Lemma A.3, and Lemma 4.7 carry the additional qualifications needed by their printed proofs, disclosed beside their statements.

The development needs Mathlib's finite-dimensional Euclidean spaces, convexity, lower semicontinuity, and real logarithm, plus real-sequence and finite-index estimates. Contributions proving the milestones, the goal, or reusable facts about the GPB model are within scope. A proof for one fixed update formula alone does not establish the goal over the BU blackbox.

Selected references

  • J. Liang and R. D. C. Monteiro, A Unified Analysis of a Class of Proximal Bundle Methods for Solving Hybrid Convex Composite Optimization Problems, Mathematics of Operations Research, 2024; source used here: arXiv:2110.01084v3, 2023, §§2–4 and Appendices A–B.
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