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LeanPool.HighContrastHomogenization.Support.Book.Ch02.Theorems.HomogenizationError.Basic

Coarse-graining support: Support.Book.Ch02.Theorems.HomogenizationError.Basic #

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

Basic Helpers for Chapter 2.5 HCPolySupport Error #

This file proves the public basic properties of the homogenization error \mathcal E_{s,\infty,1} from Sec. 2.5.

theorem HCPolySupport.Book.Ch02.finsetAverageReal_image {α : Type u_1} {β : Type u_2} [DecidableEq β] (s : Finset α) (φ : α → β) (hφ : Set.InjOn φ ↑s) (f : β → ℝ) (g : α → ℝ) (hfg : ∀ x ∈ s, f (φ x) = g x) :

Average over a finite image, specialized to the public Chapter 2 finsetAverageReal convention.

Translating triadic cube indices by a fixed shift is injective.