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

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

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

Union bound for quantitative bad scales #

This file contains only the countable union bound which passes from the bad-scale event to its fixed-pair components. It is part of the quantitative tail proof and does not introduce a last-bad-scale construction.

theorem HCPolySupport.Book.Ch05.Section57.measureReal_iUnion_nat_le_tsum {Ω : Type u_1} [MeasurableSpace Ω] {μ : MeasureTheory.Measure Ω} [MeasureTheory.IsFiniteMeasure μ] {E : ℕ → Set Ω} (hE : Summable fun (k : ℕ) => μ.real (E k)) :
μ.real (⋃ (k : ℕ), E k) ≤ ∑' (k : ℕ), μ.real (E k)
theorem HCPolySupport.Book.Ch05.Section57.measureReal_badScaleEvent_le_tsum_unpair_badPairEvent {Ω : Type u_1} [MeasurableSpace Ω] {μ : MeasureTheory.Measure Ω} [MeasureTheory.IsFiniteMeasure μ] {H : ℕ → ℕ → Ω → ℝ} {t α : ℝ} {N : ℕ} (hE : Summable fun (k : ℕ) => μ.real (badPairEvent H t α N (Nat.unpair k).1 (Nat.unpair k).2)) :
μ.real (badScaleEvent H t α N) ≤ ∑' (k : ℕ), μ.real (badPairEvent H t α N (Nat.unpair k).1 (Nat.unpair k).2)

The bad-scale event is bounded by the sum of the fixed-pair bad events.