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LeanPool.HighContrastHomogenization.Support.Book.Ch05.Theorems.Section57.HomogenizationErrorControl

Coarse-graining support: Support.Book.Ch05.Theorems.Section57.HomogenizationErrorControl #

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

Finite-q homogenization-error control above the minimal scale #

This file begins the Section 5.7 corollary converting the localized minimal-scale J estimate into finite-q control of \mathcal E_{r,\infty,q}. The first lemma is the deterministic geometric summation step: after each weighted scale response term is bounded by a summable geometric row, the finite-q homogenization error is bounded by the corresponding q-root.

For a scalar reference coefficient, the Chapter 2 full block matrix is the diagonal matrix with entries σ and σ⁻¹.

The Chapter 2 square-root normalizer agrees with the Section 5.7 scalar normalizer for a scalar reference coefficient.

Coordinatewise inverse of the scalar square-root diagonal used in Section 5.7.

The Chapter 2 inverse square-root normalizer agrees with the Section 5.7 scalar inverse normalizer for a scalar reference coefficient.

A descendant's normalized finite-probe sum is bounded by the localized maximum over all descendants at the same scale.

If every normalized finite probe satisfies a weighted localized estimate, then the finite-probe maximum satisfies the same weighted estimate.

Localized limiting-normalized maxima are nonnegative.

The finite normalized-probe maximum is nonnegative.

theorem HCPolySupport.Book.Ch05.Section57.homogenizationErrorFinite_infinity_le_rpow_of_weighted_geometric_bound {d : ℕ} (Q : TriadicCube d) {n : ℤ} (hn : n ≤ Q.scale) (a : Ch02.TriadicCoeffFamily d) (a0 : Mat d) {r delta q B : ℝ} (hrq : 0 ≤ r * q) (hdeltaq : 0 < delta * q) (hq : 0 < q) (hB : 0 ≤ B) (hterm : ∀ (l : ℕ), Ch02.geometricWeight r q l * (Ch02.scaleResponseAtScale Q (n - ↑l) Ch02.MultiscaleExponent.infinity a a0).rpow q ≤ Ch02.geometricWeight delta q l * B) :

A deterministic finite-q summation principle for the Chapter 2 homogenization error.

The hypothesis hterm is exactly the pointwise weighted scale-row estimate which comes from the localized J minimal-scale bound after choosing delta = r - tau / 2. The conclusion is the finite-q \ell^q norm bound in the definition of HomogenizationErrorFinite.

theorem HCPolySupport.Book.Ch05.Section57.weighted_scaleResponse_term_le_of_scaleResponse_le {d : ℕ} (Q : TriadicCube d) {n : ℤ} (hn : n ≤ Q.scale) (a : Ch02.TriadicCoeffFamily d) (a0 : Mat d) {r tau delta q A R : ℝ} {l : ℕ} (hdelta : delta = r - tau / 2) (hrq : 0 ≤ r * q) (hdeltaq : 0 < delta * q) (hq : 0 < q) (hA : 0 ≤ A) (hR : 0 ≤ R) (hscale : Ch02.scaleResponseAtScale Q (n - ↑l) Ch02.MultiscaleExponent.infinity a a0 ≤ A * Real.rpow 3 (tau / 2 * ↑l) * R) :

Convert a pointwise response bound with discount tau / 2 into the weighted geometric row bound used by homogenizationErrorFinite_infinity_le_rpow_of_weighted_geometric_bound.

This is the deterministic algebra behind the phrase "give up some t to get finite q": if delta = r - tau / 2 is positive, the extra 3^{tau l / 2} from taking the square root of a J-bound is absorbed by the r-geometric weight.

theorem HCPolySupport.Book.Ch05.Section57.homogenizationErrorFinite_infinity_le_of_scaleResponse_le {d : ℕ} (Q : TriadicCube d) {n : ℤ} (hn : n ≤ Q.scale) (a : Ch02.TriadicCoeffFamily d) (a0 : Mat d) {r tau delta q A R : ℝ} (hdelta : delta = r - tau / 2) (hrq : 0 ≤ r * q) (hdeltaq : 0 < delta * q) (hq : 0 < q) (hA : 0 ≤ A) (hR : 0 ≤ R) (hscale : ∀ (l : ℕ), Ch02.scaleResponseAtScale Q (n - ↑l) Ch02.MultiscaleExponent.infinity a a0 ≤ A * Real.rpow 3 (tau / 2 * ↑l) * R) :

Finite-q deterministic \mathcal E control from a scale-by-scale response estimate.

This is the packaged geometric summation step used by the Section 5.7 minimal-scale corollary. The constant is explicit: it is only the ratio of the two geometric normalizations, multiplied by the q-power of the scale-response prefactor.

Square-root form of the p = infinity scale response: a bound on the underlying descendant maximum by B^2 gives a bound on the scale response by B.