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Atlas VII definitions: KSBackgroundEnergy

Definition
Atlas_EinsteinMaxwell_ES5_KerrSchild_KSBackgroundEnergy

by He Wang · Nov 4, 2026 · Mathlib 0df444a (Lean v4.33.1)

einstein-maxwellexact-spacetime-atlas-viiexact-vacuum-atlasfive-dimensional-gravitygeneral-relativitykerr-schild

Definitions of the Atlas VII module Atlas.EinsteinMaxwell.ES5.KerrSchild.KSBackgroundEnergy (kept exactly as in the accepted source, skeleton subtraction).

VII-09 (2/3): the same-chart KS background inherits the actual null-Ricci SOS; strictly

positive background contraction arbitrarily far out; nonpositive / Einstein-form backgrounds

Input geometry is the VII-08 raw KSData gb gbi v K U (actual background MetricData, C∞ profile and vector, actual background nullity) with the open-set representation esMetric … = ksMetric gb v K on U ⊆ esDomain I, and actual PregeodesicAt gb gbi K. The actual candidate inverse is the KS inverse on U (es_inverse_eq_ks, uniqueness of the inverse); Ricci tensors are moved only through the open-set locality ricciOf_congr_of_eqOn. With VII-08 ks_pregeodesic_ricci_contract_eq this gives

Ric_gb(K,K) = Ric_gA(K,K) at every point of U,

so on the actual positive charged region the background contraction along this K equals the VII-09 weighted sum of squares and is ≥ mu·misalign ≥ 0. No sign, Ricci-flatness or Einstein property of the background is assumed; v may vanish; K may depend on all coordinates.

On the selected branch (PaperData + FactorizedN + actual PaperBVP + SmoothBranch, J ≠ 0, Q ≠ 0) the VII-08 defect is applied to the same data restricted to every farther tail, so the background contraction is strictly positive at points beyond any cutoff, and (by continuity on the open KS domain) on a nonempty open five-dimensional set there. This excludes backgrounds whose contraction along K is ≤ 0 on a tail, in particular backgrounds with pointwise Einstein-form Ricci R_ij = Λ(x) gb_ij. Strict positivity is compatible with the null energy condition; merely asymptotically Einstein backgrounds are not excluded. Same chart only; the physical candidate keeps Λ = 0; no solution is constructed.

Constants in this bundle: EinsteinBackgroundKSTail, NonposBackgroundKSTail.

Registered B3 definition layer (Mathlib at the pinned revision has no Lorentzian metric / Ricci API): mission/PHYSICS_BOUNDARY.md, Atlas VII sections P–XVII.

Definition code
-- Generated by scripts/vii24r/publish/gen_platform_tree_unitA.py (Atlas VII Unit A; copy of the RELEASE06 generator, header only) by skeleton subtraction from Atlas/EinsteinMaxwell/ES5/KerrSchild/KSBackgroundEnergy.lean
-- definition bundle: kept ExactVacuumAtlas.EinsteinMaxwell.ES5.KerrSchild.BackgroundEnergy.EinsteinBackgroundKSTail, ExactVacuumAtlas.EinsteinMaxwell.ES5.KerrSchild.BackgroundEnergy.NonposBackgroundKSTail
import Mathlib
import Definitions.Def_Atlas_Core_Basic
import Definitions.Def_Atlas_EinsteinMaxwell_Basic
import Definitions.Def_Atlas_EinsteinMaxwell_D_Basic
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_Defs
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_Generic_Cert
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_Generic_Data
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_Generic_Reduced
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_Generic_Tables
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_ChargedTail
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_CompactifiedBridge
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_CompactifiedResiduals
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_CoordinateAcceleration
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_FiniteJetObstruction
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_FiniteTaylorJet
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_GeodesicCongruenceObstruction
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_JetRecursion
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_KSConnection
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_KSMetric
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_KSRicci
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_MaxwellFrame
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_NullRicciEnergy
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_OneSidedExtraction
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_PaperGauge
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_PolynomialJet
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_PrincipalGeodesic
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_RadialBVP
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_RadialBVPEquivalence
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_RicciNullDirections
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_ScalarCertificate
import Definitions.Def_Atlas_EinsteinMaxwell_ES5_KerrSchild_SmoothBranch
import Definitions.Def_Atlas_Transport_Connection

/-! # VII-09 (2/3): the same-chart KS background inherits the actual null-Ricci SOS; strictly
positive background contraction arbitrarily far out; nonpositive / Einstein-form backgrounds

Input geometry is the VII-08 raw `KSData gb gbi v K U` (actual background `MetricData`, C∞ profile
and vector, actual background nullity) with the open-set representation
`esMetric … = ksMetric gb v K` on `U ⊆ esDomain I`, and actual `PregeodesicAt gb gbi K`. The
actual candidate inverse is the KS inverse on `U` (`es_inverse_eq_ks`, uniqueness of the
inverse); Ricci tensors are moved only through the open-set locality `ricciOf_congr_of_eqOn`. With
VII-08 `ks_pregeodesic_ricci_contract_eq` this gives

`Ric_gb(K,K) = Ric_gA(K,K)` at every point of `U`,

so on the actual positive charged region the background contraction along **this** `K` equals the
VII-09 weighted sum of squares and is `≥ mu·misalign ≥ 0`. No sign, Ricci-flatness or Einstein
property of the background is assumed; `v` may vanish; `K` may depend on all coordinates.

On the selected branch (`PaperData` + `FactorizedN` + actual `PaperBVP` + `SmoothBranch`,
`J ≠ 0`, `Q ≠ 0`) the VII-08 defect is applied to the **same** data restricted to every farther
tail, so the background contraction is strictly positive at points beyond any cutoff, and (by
continuity on the open KS domain) on a nonempty open five-dimensional set there. This excludes
backgrounds whose contraction along `K` is `≤ 0` on a tail, in particular backgrounds with
pointwise Einstein-form Ricci `R_ij = Λ(x) gb_ij`. Strict positivity is compatible with the null
energy condition; merely asymptotically Einstein backgrounds are not excluded. Same chart only;
the physical candidate keeps `Λ = 0`; no solution is constructed.
-/

open scoped ContDiff Topology Matrix
open ExactVacuumAtlas ExactVacuumAtlas.EinsteinMaxwell ExactVacuumAtlas.EinsteinMaxwell.ES5
open ExactVacuumAtlas.EinsteinMaxwell.ES5.KerrSchild.Radial
open ExactVacuumAtlas.EinsteinMaxwell.ES5.KerrSchild.Compact
open ExactVacuumAtlas.EinsteinMaxwell.ES5.KerrSchild.SmoothExt
open ExactVacuumAtlas.EinsteinMaxwell.ES5.KerrSchild.NullDirections
open ExactVacuumAtlas.EinsteinMaxwell.ES5.KerrSchild.Geodesic
open ExactVacuumAtlas.EinsteinMaxwell.ES5.KerrSchild.Geometry
open ExactVacuumAtlas.EinsteinMaxwell.ES5.KerrSchild.NullEnergy
open ExactVacuumAtlas.EinsteinMaxwell.D (einsteinMaxwellD EMCertificateD)

namespace ExactVacuumAtlas.EinsteinMaxwell.ES5.KerrSchild.BackgroundEnergy

/-! ## Restriction and continuity helpers -/

section Helpers

variable {gb gbi : Metric 5} {v : Pt 5 → ℝ} {K : Pt 5 → Fin 5 → ℝ} {U V : Set (Pt 5)}

end Helpers

/-! ## Transfer to the background -/

section Transfer

variable {I : Set ℝ} {f m N w p a : ℝ → ℝ} {gb gbi : Metric 5} {v : Pt 5 → ℝ}
  {K : Pt 5 → Fin 5 → ℝ} {U : Set (Pt 5)}

end Transfer

/-! ## Arbitrarily far strictly positive points and open patches -/

section Tail

variable {I : Set ℝ} {f m N w p a F b A : ℝ → ℝ} {s h ε Q J : ℝ}

end Tail

/-! ## Nonpositive and Einstein-form backgrounds -/

/-- Same-chart nonzero smooth background-null pregeodesic KS representation of the actual tail
`U_T` whose background Ricci contraction **along its own `K`** is `≤ 0` throughout `U_T`. -/
def NonposBackgroundKSTail (I : Set ℝ) (f m N w : ℝ → ℝ) (T : ℝ) : Prop :=
  ∃ gb gbi : Metric 5, ∃ v : Pt 5 → ℝ, ∃ K : Pt 5 → Fin 5 → ℝ,
    KSData gb gbi v K (esDomain I ∩ {x : Pt 5 | T < x 1}) ∧
    (∀ i j, Set.EqOn (esMetric f (Dfun f m N) (Afun f m) (Hfun m N) w i j) (ksMetric gb v K i j)
      (esDomain I ∩ {x : Pt 5 | T < x 1})) ∧
    (∀ x ∈ esDomain I ∩ {x : Pt 5 | T < x 1}, K x ≠ 0) ∧
    (∀ x ∈ esDomain I ∩ {x : Pt 5 | T < x 1}, PregeodesicAt gb gbi K x) ∧
    ∀ x ∈ esDomain I ∩ {x : Pt 5 | T < x 1}, contract2 (ricciOf gb gbi) x (K x) ≤ 0

/-- Same representation data with a background whose actual Ricci tensor has pointwise
Einstein form `ricciOf gb gbi i j x = Λ x * gb i j x` on `U_T` (`Λ` an arbitrary function; no
constancy, sign or Bianchi argument is used). The candidate itself keeps `Λ = 0`. -/
def EinsteinBackgroundKSTail (I : Set ℝ) (f m N w : ℝ → ℝ) (T : ℝ) : Prop :=
  ∃ gb gbi : Metric 5, ∃ v : Pt 5 → ℝ, ∃ K : Pt 5 → Fin 5 → ℝ, ∃ Λ : Pt 5 → ℝ,
    KSData gb gbi v K (esDomain I ∩ {x : Pt 5 | T < x 1}) ∧
    (∀ i j, Set.EqOn (esMetric f (Dfun f m N) (Afun f m) (Hfun m N) w i j) (ksMetric gb v K i j)
      (esDomain I ∩ {x : Pt 5 | T < x 1})) ∧
    (∀ x ∈ esDomain I ∩ {x : Pt 5 | T < x 1}, K x ≠ 0) ∧
    (∀ x ∈ esDomain I ∩ {x : Pt 5 | T < x 1}, PregeodesicAt gb gbi K x) ∧
    ∀ x ∈ esDomain I ∩ {x : Pt 5 | T < x 1}, ∀ i j, ricciOf gb gbi i j x = Λ x * gb i j x

section Exclusion

variable {I : Set ℝ} {f m N w p a F b A : ℝ → ℝ} {s h ε Q J : ℝ}

end Exclusion

/-! ## Own-certificate versions (common `Q, J` extracted by the frozen VII-06 root) -/

section Certificate

variable {I : Set ℝ} {f m N w p a F b A : ℝ → ℝ} {s h ε : ℝ}

end Certificate

end ExactVacuumAtlas.EinsteinMaxwell.ES5.KerrSchild.BackgroundEnergy
Source
He Wang, Exact Spacetime Atlas VII, Unit A (restricted Kerr–Schild obstruction on the actual asymptotic branch, VII17). Local source, no public repository; commit f64ba9c823ec; Atlas/EinsteinMaxwell/ES5/KerrSchild/KSBackgroundEnergy.lean; SHA-256 d817b93e8e7388c86e08169a286a395342d39320ec1edd99fbb7c5efe7c434e4. Registered definitions: mission/PHYSICS_BOUNDARY.md (Atlas VII sections P–XVII). Physical Kerr–Schild obstruction: Fröb–Khavkine–Málek–Pravda, Eur. Phys. J. C 82 (2022) 215, arXiv:2112.13266 (Eqs. 23–25, 33, 59–60).

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