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LeanPool.Superdiffusion.Algsuperdiff.Section5.Provider.ErrorMoment

ErrorMoment #

Ported from scottnarmstrong/Superdiffusion at 7f20476385d4af418f110303085ad0740c9eba46. Module imports, support namespace and local option directives adapted for Lean Pool.

A renormalization amplitude for the localized error #

The generator-renormalization estimate is uniform over the normalized forcing class. This module compares its constant-coefficient solution with the canonical comparator used in localizedError.

Comparator rescaling #

theorem Algsuperdiff.Section5.Provider.isDirichletSolutionAt_rescale_constant {d : ℕ} {y : HCPolySupport.Vec d} {n : ℤ} {sigma tau : ℝ} (htau : 0 < tau) {v : HCPolySupport.H1Function (Support.cubeSetAt y n)} {g : HCPolySupport.Vec d → HCPolySupport.Vec d} (hv : Support.IsDirichletSolutionAt (fun (x : HCPolySupport.Vec d) => sigma • 1) y n v g) :
Support.IsDirichletSolutionAt (fun (x : HCPolySupport.Vec d) => tau • 1) y n ((sigma / tau) • v) g

A solution for sigma • 1 rescales to a solution with the same forcing for tau • 1.

Reading a pointwise estimate as an essential-supremum estimate #

The comparator swap #

The normalized error for the canonical comparator is controlled by the renormalization error and the explicit cost of changing the scalar.

Every canonical comparator has the explicit normalized essential-supremum bound supplied by the cube Schauder estimate.

theorem Algsuperdiff.Section5.Provider.exists_localizedError_origin_bound (d : ℕ) (cstar : ℝ) (hdim : 2 ≤ d) (hcstar : 0 < cstar) :
∃ (gamma0 : ℝ) (C : ℝ) (K : ℝ) (B : ℝ), 0 < gamma0 ∧ 0 < C ∧ 0 < K ∧ 0 < B ∧ ∀ (M : Section3.ABKModel d), Section3.Disorder.cstar M = cstar → M.gamma ≤ gamma0 → ∀ (n : ℤ), ∃ (sigma : ℝ) (EB : Section3.Cutoff.CutoffSample d → ℝ), 0 < sigma ∧ (∀ (omega : Section3.Cutoff.CutoffSample d), 0 ≤ EB omega) ∧ Measurable EB ∧ (∀ (p : ℝ), 1 ≤ p → p ≤ C⁻¹ * M.gamma⁻¹ * |Real.log M.gamma|⁻¹ → ∫⁻ (omega : Section3.Cutoff.CutoffSample d), ENNReal.ofReal (EB omega) ^ p ∂↑(Section3.Cutoff.cutoffSampleLaw M) ≤ ENNReal.ofReal (C * (√p + √|Real.log M.gamma|) * √M.gamma * |Real.log M.gamma| ^ 3) ^ p) ∧ ↑(Section3.Annealed.sigmaBar M n) / sigma ≤ 2 ∧ |↑(Section3.Annealed.sigmaBar M n) / sigma - 1| ≤ 4 * K * √M.gamma * |Real.log M.gamma| ∧ ∀ᵐ (omega : Section3.Cutoff.CutoffSample d) ∂↑(Section3.Cutoff.cutoffSampleLaw M), Support.localizedError M n 0 omega ≤ ENNReal.ofReal (↑(Section3.Annealed.sigmaBar M n) / sigma * EB omega + |↑(Section3.Annealed.sigmaBar M n) / sigma - 1| * B)

The generator-renormalization estimate, specialized at zero boundary datum and the normalized forcing scale, bounds the localized error at the origin after the canonical-comparator swap.

Moment packaging #

A uniform almost-everywhere bound by a rescaled random amplitude plus a deterministic comparator cost gives the corresponding two-term moment bound.

theorem Algsuperdiff.Section5.Provider.localizedError_moment_bound (d : ℕ) (cstar : ℝ) (hdim : 2 ≤ d) (hcstar : 0 < cstar) :
∃ (gamma0 : ℝ) (C' : ℝ), 0 < gamma0 ∧ 0 < C' ∧ ∀ (M : Section3.ABKModel d), Section3.Disorder.cstar M = cstar → M.gamma ≤ gamma0 → ∀ (p : ℝ) (n : ℤ) (y : HCPolySupport.Vec d), 1 ≤ p → p ≤ C'⁻¹ * M.gamma⁻¹ * |Real.log M.gamma|⁻¹ → ∫⁻ (omega : Section3.Cutoff.CutoffSample d), Support.localizedError M n y omega ^ p ∂↑(Section3.Cutoff.cutoffSampleLaw M) ≤ ENNReal.ofReal (C' * (√p + √|Real.log M.gamma|) * √M.gamma * |Real.log M.gamma| ^ 3) ^ p

The localized error has the generator-renormalization moment profile, with a new constant absorbing the canonical-comparator swap.