Documentation

LeanPool.HighContrastHomogenization.Provider.Quenched.RowDecayAESummability

High-contrast homogenization: Provider.Quenched.RowDecayAESummability #

Imported from the Apache-2.0 HighContrastHomogenization development at commit 7a13dbcd8d6609264a713373f5c69ceeac870472.

Almost-everywhere summability from stopping-generation decay #

The stopping-generation tail is uniform in the outer generation. Along the diagonal where the allowed stopping offset grows linearly, its probabilities are super-geometrically summable. Borel--Cantelli therefore makes the row decay strong enough to sum every weighted tail almost everywhere.

theorem HCPolySupport.HighContrast.Quenched.ae_summable_weighted_row_of_stoppingGeneration {Omega : Type u_1} [MeasurableSpace Omega] {P : MeasureTheory.Measure Omega} [MeasureTheory.IsProbabilityMeasure P] {nstar qfb b : ℕ} {R B : ℕ → Omega → ℝ} {theta mu cd delta Cblk : ℝ} (htheta : 0 < theta) (hmu : 0 < mu) (hcd : 0 < cd) (hdelta : 0 < delta) (hCblk : 0 < Cblk) (hRtail : ∀ (n q : ℕ), nstar ≤ n → P.real {ω : Omega | 3 ^ (n + q + b) < R n ω} ≤ Real.exp (-(cd * 3 ^ (2 * mu * ↑q)))) (hBdecay : ∀ᵐ (ω : Omega) ∂P, ∀ (m : ℕ), nstar ≤ m → B m ω ≤ Cblk * delta * 3 ^ (-theta * (↑m - ↑(stoppingGeneration nstar qfb R m ω) - ↑nstar))) (hBnonneg : ∀ (m : ℕ) (ω : Omega), 0 ≤ B m ω) :
∀ᵐ (ω : Omega) ∂P, ∀ (k : ℕ), Summable fun (j : ℕ) => 3 ^ (theta / 2 * ↑j) * B (k + j) ω

Almost-everywhere row decay against a stopping family supplies the almost-everywhere weighted summability required by the coupled engine.