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Complexitylib.Algebraic.LowerBound.Cutwidth.Extractor.Moments.Tails.Internal

Normalizing the first four sign-sum moments #

The raw parity-bias bounds, divided by powers of the square root of the number of signs, satisfy the approximate-moment certificate in FourthMoment.

theorem Algebraic.Cutwidth.Extractor.Internal.signSum_tails_of_parityBias {α : Type u_1} {m : ℕ} {s : Finset α} {w : α → ℝ} {σ : α → Fin m → ℝ} {δ : ℝ} (hw : ∀ a ∈ s, 0 ≤ w a) (hmass : ∑ a ∈ s, w a = 1) (hm : 0 < m) (hσ : ∀ a ∈ s, ∀ (i : Fin m), σ a i = 1 ∨ σ a i = -1) (hδ : 0 ≤ δ) (hbudget : 100 * ↑m ^ 2 * δ ≤ 1) (h : ParityBiasBound s w σ δ) :
(1 / 36 ≤ ∑ a ∈ s, if √↑m / 8 < signSum σ a then w a else 0) ∧ 1 / 36 ≤ ∑ a ∈ s, if signSum σ a < -(√↑m / 8) then w a else 0