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A Paley tournament bound for the sensitivity exponent: 2.1311217191902.1311217191902.131121719190

Proved
SensitivityCampaign.paley11987_four_phase

by yousofy · Oct 22, 2026 · Mathlib 0df444a (Lean v4.33.1)

block-sensitivityboolean-functionscombinatoricssensitivity

For every real ε>0\varepsilon>0ε>0 and every integer S≥2S\ge 2S≥2, there are an integer n≥0n\ge 0n≥0 and a total Boolean function f:{0,1}n→{0,1}f:\{0,1\}^n\to\{0,1\}f:{0,1}n→{0,1} such that

s(f)≥S,bs(f)≥s(f) 2.131121719190−ε.s(f)\ge S, \qquad bs(f)\ge s(f)^{\,2.131121719190-\varepsilon}.s(f)≥S,bs(f)≥s(f)2.131121719190−ε.

Here s(f)s(f)s(f) is the maximum, over all inputs, of the number of individual input bits whose flip changes the output. The block sensitivity bs(f)bs(f)bs(f) is the maximum, over all inputs, of the size of a family of pairwise disjoint nonempty sets of input bits, each of whose simultaneous flip changes the output. The number 2.1311217191902.1311217191902.131121719190 denotes the exact rational 2131121719190/10122131121719190/10^{12}2131121719190/1012.

The statement uses the campaign's shared definitions of sensitivity, block sensitivity, and SensitivityCampaign.AchievesExponent.

Preamble
import Definitions.Def_SensitivitySeparation
import Definitions.Def_SensitivityCampaign
import Mathlib.Analysis.SpecialFunctions.Log.Basic
Formal statement
theorem SensitivityCampaign.paley11987_four_phase :
  SensitivityCampaign.AchievesExponent (2131121719190 / 1000000000000 : ℝ) := by sorry
Source
Original Paley-11987 four-phase Boolean construction and its exact formal certificate. Campaign context: https://prove2.me/campaigns/block-sensitivity-vs-sensitivity. The complete proof source accompanying this submission is the source of the new bound; no external paper is claimed to establish this new exponent.
Human review
  • Endorsed by Shuze Chen · Oct 23, 2026

    Confirmed by the moderator at approval.

  • Endorsed by yousofy · Oct 23, 2026

    Confirmed by the mission captain (proposal self-audit).

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