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LeanPool.HighContrastHomogenization.Support.Book.Ch04.Internal.FixedCompetitorEnergyMeasurability.Measurability

Coarse-graining support: #

Support.Book.Ch04.Internal.FixedCompetitorEnergyMeasurability.Measurability

Imported from the Apache-2.0 CoarseGraining development at commit c7ddd76c08ade64fed1b8d2ca51be14dfee8deb4.

Fixed-competitor energy measurability, first atoms #

Audit tag (Ch4 rebuild contract CH04_REBUILD_SURFACE_2026-05-16.md) #

Internal claim: the PointwiseLocalSigma-measurable scalar atoms (single-vector dot products, single-coordinate matrix-vector products, etc.) used as the local-σ-measurable building blocks for fixed-competitor energy observables. First layer of the internal HasMeasurableMuFamily cleanup.

Consumed by (within Internal/FixedCompetitorEnergyMeasurability/): LipschitzBounds.lean, which lifts these atoms to Borel-measurable fixed-coefficient maps; ultimately reaches the public Theorems/Mu.lean :: aemeasurable_Mu_cubeSet via the chain Measurability → LipschitzBounds → Integrals → BlockEnergyAverage → MuObservable → AEESliceAssembly/MuFamily.

If the single-claim summary above grows into three or more distinct claims, split or refactor per the rebuild contract.

theorem HCPolySupport.vecDot_single_matVecMul_single {d : ℕ} (A : Mat d) (i j : Fin d) :
vecDot (Pi.single i 1) (matVecMul A (Pi.single j 1)) = A i j
theorem HCPolySupport.localTestObservable_single_single_eq_integral_entry {d : ℕ} (i j : Fin d) (φ : Vec d → ℝ) :
localTestObservable (Pi.single j 1) (Pi.single i 1) φ = fun (a : CoeffField d) => ∫ (x : Vec d), a x i j * φ x
theorem HCPolySupport.measurable_entryTestObservable_localSigma {d : ℕ} {U : Set (Vec d)} (i j : Fin d) {φ : Vec d → ℝ} (hφ_cont : ContDiff ℝ (↑⊤) φ) (hφ_compact : HasCompactSupport φ) (hφ_support : tsupport φ ⊆ U) :
Measurable fun (a : CoeffField d) => ∫ (x : Vec d), a x i j * φ x
theorem HCPolySupport.setIntegral_entry_mul_eq_integral_of_tsupport_subset {d : ℕ} {U : Set (Vec d)} (a : CoeffField d) (i j : Fin d) {φ : Vec d → ℝ} (hφ_support : tsupport φ ⊆ U) :
∫ (x : Vec d) in U, a x i j * φ x = ∫ (x : Vec d), a x i j * φ x
theorem HCPolySupport.measurable_entryTestObservable_setIntegral_localSigma {d : ℕ} {U : Set (Vec d)} (i j : Fin d) {φ : Vec d → ℝ} (hφ_cont : ContDiff ℝ (↑⊤) φ) (hφ_compact : HasCompactSupport φ) (hφ_support : tsupport φ ⊆ U) :
Measurable fun (a : CoeffField d) => ∫ (x : Vec d) in U, a x i j * φ x

Mathlib's global smooth compact-support density, converted to the exact toLp representative shape used by the probability bookkeeping.

The later local argument still has to push these probes inside U; this lemma isolates the ambient density input from that boundary-cutoff step.

theorem HCPolySupport.exists_contDiff_hilbertMatrixL2_tsupport_subset_eLpNorm_sub_le {d : ℕ} {U : Set (Vec d)} (hUopen : IsOpen U) (hUfinite : MeasureTheory.volume U ≠ ⊤) {g : Vec d → HilbertMat d} (hgL2 : MeasureTheory.MemLp g 2 (volumeMeasureOn U)) (hg_cont : ContDiff ℝ (↑⊤) g) {ε : ℝ} (hε : 0 < ε) :

Localize a smooth L² matrix field to an open finite-measure set without changing it much in L². This is the analytic cutoff step that turns Mathlib's ambient compactly supported smooth density into the note-facing tsupport ⊆ U probe class.

Smooth compactly supported HilbertMat probes with support contained in an open finite-measure set are dense in L²(U; HilbertMat d).

On an open finite-measure domain, the quantitative-slice coefficient field as an L² Hilbert-matrix object is measurable for the local sigma algebra.

On an open finite-measure domain, the essential quantitative-slice coefficient field as an L² Hilbert-matrix object is measurable for the local sigma algebra.

Smooth probes supported in the open core of a triadic cube are dense for the half-open cube, because the two restricted volume measures agree.

On a half-open triadic cube, the essential quantitative-slice coefficient field as an L² Hilbert-matrix object is measurable for the local sigma algebra.

Smooth-probe coordinate pairings of the AEE L² coefficient realization are local-test measurable.

On an open finite-measure domain, the AEE quantitative-slice coefficient field as an L² Hilbert-matrix object is measurable for the local sigma algebra.

On a half-open triadic cube, the AEE quantitative-slice coefficient field as an L² Hilbert-matrix object is measurable for the local sigma algebra.