Definitions bundle OAIQ4Kq010 of the split of OpenAI, A counterexample to Kaplansky's quasitrace conjecture and failure of tensor-product stable finiteness
DefinitionOAIQ4Kq010A definitions bundle of the split of OpenAI's proof of OAI.Kaplansky.kaplansky_quasitrace_counterexample, carved from OpenAI's openai/math development (OpenAI, A counterexample to Kaplansky's quasitrace conjecture and failure of tensor-product stable finiteness, OpenAI Math Release, September 23, 2026, result family 294, github.com/openai/math at commit adc7f12, Apache License 2.0) and ported to Lean 4.33.1 and Mathlib 0df444a. The declarations and their proofs are OpenAI's.
Contents. It holds 23 declarations of OpenAI's Lean: 3 definitions, 6 instances and 14 theorems. The definitions and types are OAI.Kaplansky.semigroupToOrderedGroup, OAI.Kaplansky.twistedSlotEquiv, OAI.Kaplansky.twistedStandardFrames.
Sources. They come from these modules of lean/OAI/Analysis/Kaplansky, in whole or in part: BundleTests_Base, BundleTests_Smooth, BundleTests_Twisted, Cuntz_Monoid, Cuntz_State, IntegralHomology_ProjectiveClass, Kaplansky_TestAlgebra, OrderedStates_Semigroup.
Imports. It imports the bundles OAIQ4Kq005, OAIQ4Kq006, OAIQ4Kq007 and OAIQ4Kq008 of this split.
Imported by (directly, in this split): the bundle OAIQ4Kq011.
import Mathlib
import Lean.Elab.Tactic.Omega
import Definitions.Def_OAIQ4Kq005
import Definitions.Def_OAIQ4Kq006
import Definitions.Def_OAIQ4Kq007
import Definitions.Def_OAIQ4Kq008
section
-- module Solutions.OAIQ4_Kq.BundleTests_Base
attribute [-instance] _root_.Convexity.StdSimplex.instInhabited _root_.Convexity.StdSimplex.instNonempty _root_.Convexity.StdSimplex.instSubsingleton _root_.Convexity.StdSimplex.instUnique _root_.Convexity.StdSimplex.topologicalSpace _root_.OAI.Kaplansky.actualHilbert_nontrivial _root_.OAI.Kaplansky.complexCoreFiberRealModule
set_option linter.all false
set_option linter.unusedVariables false
set_option linter.unusedTactic false
set_option linter.unreachableTactic false
namespace OAI
/-! The compact bundle-test base, prefix dimensions, and retained multiplicities. -/
noncomputable section
open scoped BigOperators ComplexOrder Matrix.Norms.L2Operator
open Matrix Bundle Topology
namespace Kaplansky
instance instCompactSpaceBundleTestBase (m R : ℕ) : CompactSpace (BundleTestBase m R) := inferInstance
instance instNonemptyBundleTestBase (m R : ℕ) : Nonempty (BundleTestBase m R) := ⟨bundleTestBasePoint m R⟩
end Kaplansky
end
end OAI
end
section
-- module Solutions.OAIQ4_Kq.BundleTests_Smooth
attribute [-instance] _root_.Convexity.StdSimplex.instInhabited _root_.Convexity.StdSimplex.instNonempty _root_.Convexity.StdSimplex.instSubsingleton _root_.Convexity.StdSimplex.instUnique _root_.Convexity.StdSimplex.topologicalSpace _root_.OAI.Kaplansky.ComplexGrassmann.grassmannZero_subsingleton _root_.OAI.Kaplansky.actualHilbert_nontrivial _root_.OAI.Kaplansky.finiteCoordinateBundle_smooth _root_.OAI.Kaplansky.lineStageTotal_locallyCompactSpace _root_.OAI.Kaplansky.lineStage_finite _root_.OAI.Kaplansky.retainedBundle_inner _root_.OAI.Kaplansky.retainedBundle_norm _root_.OAI.Kaplansky.smoothNext_inner _root_.OAI.Kaplansky.smoothNext_norm
set_option linter.all false
set_option linter.unusedVariables false
set_option linter.unusedTactic false
set_option linter.unreachableTactic false
namespace OAI
noncomputable section
/-! Smooth bases and test bundles with replacement maps. -/
section
open Topology
open scoped Manifold ContDiff BigOperators
namespace Kaplansky
open ComplexGrassmann
instance instCompactSpaceSmoothTestBase (m R : ℕ) : CompactSpace (SmoothTestBase m R) := inferInstance
instance instT2SpaceSmoothTestBase (m R : ℕ) : T2Space (SmoothTestBase m R) := inferInstance
end Kaplansky
end
open Bundle Topology
end
end OAI
end
section
-- module Solutions.OAIQ4_Kq.IntegralHomology_ProjectiveClass
attribute [-instance] _root_.OAI.Kaplansky.finiteCoordinateBundle_smooth _root_.OAI.Kaplansky.instCompactSpaceSmoothTestBase _root_.OAI.Kaplansky.instT2SpaceSmoothTestBase _root_.OAI.Kaplansky.lineStageTotal_locallyCompactSpace _root_.OAI.Kaplansky.smoothNext_inner _root_.OAI.Kaplansky.smoothNext_norm
set_option linter.all false
set_option linter.unusedVariables false
set_option linter.unusedTactic false
set_option linter.unreachableTactic false
namespace OAI
noncomputable section
namespace Kaplansky
/-! Localization, top homology, and the fundamental class of projective products. -/
section
open CategoryTheory Limits
open ComplexGrassmann
instance projectiveSpaceZero_nonempty : Nonempty (Grassmann 1 0) :=
⟨graphPoint (standardLineGraphFrame 0) 0⟩
open ComplexGrassmann
end
open CategoryTheory Limits
end Kaplansky
end
end OAI
end
section
-- module Solutions.OAIQ4_Kq.BundleTests_Twisted
set_option linter.all false
set_option linter.unusedVariables false
set_option linter.unusedTactic false
set_option linter.unreachableTactic false
namespace OAI
noncomputable section
/-! Twisted hyperplane bundles, zeros, graph coordinates, and frame sections. -/
section
open Bundle Topology
namespace Kaplansky
open ComplexGrassmann
variable {ι : Type} [Fintype ι] (K : ι → ℕ) (h : ℕ)
def twistedSlotEquiv : TwistedHyperplaneSlot K h ≃
(Σ i, Fin (twistedProjectiveDimensions K h i)) where
toFun
| .inl j => ⟨none,j⟩
| .inr s => ⟨some s.1,s.2⟩
invFun
| ⟨none,j⟩ => .inl j
| ⟨some i,j⟩ => .inr ⟨i,j⟩
left_inv s := by cases s <;> rfl
right_inv s := by obtain ⟨i,j⟩ := s; cases i <;> rfl
def twistedStandardFrames (i : Option ι) := standardLineGraphFrame (twistedProjectiveDimensions K h i)
end Kaplansky
end
open Bundle Topology
end
end OAI
end
section
-- module Solutions.OAIQ4_Kq.Cuntz_Monoid
attribute [-instance] _root_.Convexity.StdSimplex.instInhabited _root_.Convexity.StdSimplex.instNonempty _root_.Convexity.StdSimplex.instSubsingleton _root_.Convexity.StdSimplex.instUnique _root_.Convexity.StdSimplex.topologicalSpace _root_.OAI.Kaplansky.complexCoreFiberRealModule
set_option linter.all false
set_option linter.unusedVariables false
set_option linter.unusedTactic false
set_option linter.unreachableTactic false
namespace OAI
/-! The ordered Cuntz monoid and compression by its order unit. -/
noncomputable section
namespace Kaplansky
attribute [local instance] CStarAlgebra.spectralOrder CStarAlgebra.spectralOrderedRing
variable {A : Type*} [CStarAlgebra A]
/-- Every class is bounded by a natural multiple of [1_A]. -/
theorem cuntzMonoid_orderUnit (x : CuntzMonoid A) : ∃ n : ℕ, x ≤ n • cuntzUnit A 1 := by
induction x using Quotient.inductionOn with | h x =>
refine ⟨x.size, ?_⟩
rw [cuntzUnit_nsmul]
exact (cuntzClass_le _ _).mpr x.le_unit
end Kaplansky
end
end OAI
end
section
-- module Solutions.OAIQ4_Kq.OrderedStates_Semigroup
attribute [-instance] _root_.Convexity.StdSimplex.instInhabited _root_.Convexity.StdSimplex.instNonempty _root_.Convexity.StdSimplex.instSubsingleton _root_.Convexity.StdSimplex.instUnique _root_.Convexity.StdSimplex.topologicalSpace _root_.OAI.Kaplansky.complexCoreFiberRealModule
set_option linter.all false
set_option linter.unusedVariables false
set_option linter.unusedTactic false
set_option linter.unreachableTactic false
namespace OAI
noncomputable section
/-! Catalytic orders, ordered group completion, and normalized semigroup states. -/
namespace Kaplansky
section
variable (S : Type*) [AddCommMonoid S] [PartialOrder S] [IsOrderedAddMonoid S]
variable {S}
/-- The actual additive map from the monoid into its ordered completion. -/
def semigroupToOrderedGroup : S →+ SemigroupOrderedGroup S where
toFun a := semigroupDifferenceClass (a,0)
map_zero' := rfl
map_add' a b := by
change semigroupDifferenceClass (a+b,0) = semigroupDifferenceClass ((a,0)+(b,0))
congr 1
exact Prod.ext rfl (zero_add 0).symm
theorem semigroupToOrderedGroup_le_iff (a b : S) :
semigroupToOrderedGroup a ≤ semigroupToOrderedGroup b ↔ ∃ c : S, a+c ≤ b+c := by
change semigroupDifferenceClass (a,0) ≤ semigroupDifferenceClass (b,0) ↔ _
simpa only [add_zero] using semigroupDifferenceClass_le (a,0) (b,0)
theorem semigroupToOrderedGroup_monotone : Monotone (semigroupToOrderedGroup (S := S)) := by
intro a b hab
exact (semigroupToOrderedGroup_le_iff a b).mpr ⟨0, by simpa using hab⟩
end
section
variable {S : Type*} [AddCommMonoid S] [PartialOrder S] [IsOrderedAddMonoid S]
theorem semigroupDifferenceClass_eq_sub (a b : S) :
semigroupDifferenceClass (a,b) = semigroupToOrderedGroup a - semigroupToOrderedGroup b := by
change semigroupDifferenceClass (a,b) = semigroupDifferenceClass ((a,0)+(0,b))
congr 1
exact Prod.ext (add_zero a).symm (zero_add b).symm
theorem semigroupOrderedGroup_exists_difference (x : SemigroupOrderedGroup S) :
∃ a b : S, x = semigroupToOrderedGroup a - semigroupToOrderedGroup b := by
induction x using Quotient.inductionOn with | h x =>
exact ⟨x.1,x.2,semigroupDifferenceClass_eq_sub _ _⟩
/-- The image of the unit remains order-reflecting on all natural multiples,
including after passage to the ordered group quotient. -/
theorem semigroupOrderedGroup_unit_order (u : S)
(hf : ∀ k : ℕ, 0 < k → ¬ (2*k) • u ≤ k • u)
(hpos : ∀ c : S, 0 ≤ c) (hbound : ∀ c : S, ∃ N : ℕ, c ≤ N • u)
(m n : ℕ) :
m • semigroupToOrderedGroup u ≤ n • semigroupToOrderedGroup u ↔ m ≤ n := by
rw [← map_nsmul, ← map_nsmul, semigroupToOrderedGroup_le_iff]
exact stabilized_unit_order_iff u (hpos u) hf hpos hbound m n
theorem semigroupOrderedGroup_unit_nonneg (u : S) (hu : 0 ≤ u) :
0 ≤ semigroupToOrderedGroup u := by
simpa using semigroupToOrderedGroup_monotone hu
/-- The original order-unit bound becomes a two-sided bound on every
element of the ordered group. No finite generation is needed. -/
theorem semigroupOrderedGroup_order_unit (u : S)
(hpos : ∀ c : S, 0 ≤ c) (hbound : ∀ c : S, ∃ N : ℕ, c ≤ N • u)
(x : SemigroupOrderedGroup S) :
∃ N : ℕ, -(N • semigroupToOrderedGroup u) ≤ x ∧
x ≤ N • semigroupToOrderedGroup u := by
obtain ⟨a,b,rfl⟩ := semigroupOrderedGroup_exists_difference x
obtain ⟨m,hm⟩ := hbound a
obtain ⟨n,hn⟩ := hbound b
have ha := semigroupToOrderedGroup_monotone hm
have hb := semigroupToOrderedGroup_monotone hn
rw [map_nsmul] at ha hb
have hza := semigroupOrderedGroup_unit_nonneg a (hpos a)
have hzb := semigroupOrderedGroup_unit_nonneg b (hpos b)
have hu := semigroupOrderedGroup_unit_nonneg u (hpos u)
refine ⟨m+n, ?_, ?_⟩
· have hb' : semigroupToOrderedGroup b ≤ (m+n) • semigroupToOrderedGroup u :=
hb.trans (nsmul_le_nsmul_left hu (Nat.le_add_left n m))
exact (neg_le_neg hb').trans (neg_le_sub_iff_le_add.mpr (by simpa using hza))
· have ha' : semigroupToOrderedGroup a ≤ (m+n) • semigroupToOrderedGroup u :=
ha.trans (nsmul_le_nsmul_left hu (Nat.le_add_right m n))
exact (sub_le_self _ hzb).trans ha'
variable {G : Type*} [AddCommGroup G] [PartialOrder G] [IsOrderedAddMonoid G]
@[simp] theorem semigroupOrderedGroupLift_unit (f : S →+ G) (hf : Monotone f) (a : S) :
semigroupOrderedGroupLift f hf (semigroupToOrderedGroup a) = f a := by
change f a-f 0=f a
simp
theorem semigroupOrderedGroupLift_monotone (f : S →+ G) (hf : Monotone f) :
Monotone (semigroupOrderedGroupLift f hf) := by
intro a b hab
induction a using Quotient.inductionOn with | h a =>
induction b using Quotient.inductionOn with | h b =>
exact semigroupDifference_value_mono f hf ((semigroupDifferenceClass_le _ _).mp hab)
theorem semigroup_state_iff_orderedGroup_state (u : S) :
(∃ f : S →+ ℝ, Monotone f ∧ f u = 1) ↔
∃ g : SemigroupOrderedGroup S →+ ℝ, Monotone g ∧ g (semigroupToOrderedGroup u) = 1 := by
constructor
· rintro ⟨f,hf,hu⟩
exact ⟨semigroupOrderedGroupLift f hf,semigroupOrderedGroupLift_monotone f hf,by simpa⟩
· rintro ⟨g,hg,hu⟩
exact ⟨g.comp semigroupToOrderedGroup,hg.comp semigroupToOrderedGroup_monotone,hu⟩
end
variable {S : Type*} [AddCommMonoid S] [PartialOrder S] [IsOrderedAddMonoid S]
/-- State construction on a positive ordered commutative monoid with an
order unit and no properly infinite positive unit multiple. Cancellation
and unperforation are not hypotheses. This is an abstract semigroup theorem,
not yet a quasitrace on an algebra. -/
theorem positive_orderUnit_normalized_state (u : S)
(hpos : ∀ c : S, 0 ≤ c) (hbound : ∀ c : S, ∃ N : ℕ, c ≤ N • u)
(hf : ∀ k : ℕ, 0 < k → ¬ (2*k) • u ≤ k • u) :
∃ f : S →+ ℝ, Monotone f ∧ f u = 1 := by
apply (semigroup_state_iff_orderedGroup_state u).mpr
apply orderedGroup_normalized_state (semigroupToOrderedGroup u)
(semigroupOrderedGroup_unit_nonneg u (hpos u))
· intro n hn h
have h' : n • semigroupToOrderedGroup u ≤ 0 • semigroupToOrderedGroup u := by simpa using h
have hle := (semigroupOrderedGroup_unit_order u hf hpos hbound n 0).mp h'
omega
· intro x
obtain ⟨N,hl,_⟩ := semigroupOrderedGroup_order_unit u hpos hbound x
exact ⟨N,hl⟩
end Kaplansky
end
end OAI
end
section
-- module Solutions.OAIQ4_Kq.Cuntz_State
attribute [-instance] _root_.Convexity.StdSimplex.instInhabited _root_.Convexity.StdSimplex.instNonempty _root_.Convexity.StdSimplex.instSubsingleton _root_.Convexity.StdSimplex.instUnique _root_.Convexity.StdSimplex.topologicalSpace _root_.OAI.Kaplansky.CuntzDimensionState.spectralMeasure_finite _root_.OAI.Kaplansky.complexCoreFiberRealModule
set_option linter.all false
set_option linter.unusedVariables false
set_option linter.unusedTactic false
set_option linter.unreachableTactic false
namespace OAI
noncomputable section
/-! Dimension states of the Cuntz monoid and positivity. -/
namespace Kaplansky
attribute [local instance] CStarAlgebra.spectralOrder CStarAlgebra.spectralOrderedRing
variable {A : Type*} [CStarAlgebra A]
theorem normalizedCuntzState_exists
(hf : ∀ k : ℕ, 0 < k → ¬ ProperlyInfinite (CStarMatrix (Fin k) (Fin k) A)) :
∃ f : CuntzMonoid A →+ ℝ, Monotone f ∧ f (cuntzUnit A 1) = 1 := by
apply positive_orderUnit_normalized_state (cuntzUnit A 1)
cuntzMonoid_nonneg cuntzMonoid_orderUnit
intro k hk h
exact hf k hk (properlyInfinite_of_cuntzUnit_compression k h)
theorem cuntzDimensionState_nonempty
(hf : ∀ k : ℕ, 0 < k → ¬ ProperlyInfinite (CStarMatrix (Fin k) (Fin k) A)) :
Nonempty (CuntzDimensionState A) := by
obtain ⟨f, hm, hu⟩ := normalizedCuntzState_exists hf
exact ⟨⟨f, hm, hu⟩⟩
end Kaplansky
open scoped Matrix CStarAlgebra
end
end OAI
end
section
-- module Solutions.OAIQ4_Kq.Kaplansky_TestAlgebra
attribute [-instance] _root_.Convexity.StdSimplex.instInhabited _root_.Convexity.StdSimplex.instNonempty _root_.Convexity.StdSimplex.instSubsingleton _root_.Convexity.StdSimplex.instUnique _root_.Convexity.StdSimplex.topologicalSpace _root_.OAI.Kaplansky.ComplexGrassmann.grassmannZero_subsingleton _root_.OAI.Kaplansky.lineStageTotal_locallyCompactSpace _root_.OAI.Kaplansky.projectiveSpaceZero_nonempty _root_.OAI.Kaplansky.retainedBundle_inner _root_.OAI.Kaplansky.retainedBundle_norm
set_option linter.all false
set_option linter.unusedVariables false
set_option linter.unusedTactic false
set_option linter.unreachableTactic false
namespace OAI
noncomputable section
/-! Concrete test operators, their C-star algebra, and its faithful representation. -/
open Bundle Topology
open scoped BigOperators ComplexOrder
namespace Kaplansky
open ComplexGrassmann
instance instNonemptyActualTestIndex : Nonempty ActualTestIndex :=
⟨⟨1,1,testBaseProjectiveHomeomorph 1 1 (bundleTestBasePoint 1 1)⟩⟩
open scoped BigOperators
attribute [local instance 2000] CStarAlgebra.spectralOrder CStarAlgebra.spectralOrderedRing
attribute [local instance 2000] closedSubalgebraLE closedSubalgebraPreorder
end Kaplansky
end
end OAI
end