TCSLib

249 Boolean Analysis — Profile Approximation

249.1 Overview

Continuity and vanishing endpoint values control the Gaussian profile by distance to either endpoint probability. Consequently, Gaussian averaging of a measurable indicator has an integral profile tending to zero.

249.2 Declarations

Lemma 249.1 Profile bound by distance to endpoints
✓

Let \(\Phi ,\varphi \) be the standard Gaussian distribution function and density, and let \(\overline I(p)=\varphi (\Phi ^{-1}(p))\) for \(0\lt p\lt 1\), with \(\overline I(p)=0\) elsewhere. For every \(\varepsilon \gt 0\) there exists \(C\gt 0\) such that \(\overline I(p)\le \varepsilon +C|p-b|\) for all \(p\in [0,1]\) and \(b\in \{ 0,1\} \).

Lemma 249.2 Integral profile bounded by rotation sensitivity
✓

Let \(\Phi ,\varphi \) be the standard Gaussian distribution function and density, and let \(\overline I(p)=\varphi (\Phi ^{-1}(p))\) for \(0\lt p\lt 1\), with \(\overline I(p)=0\) elsewhere. Let \(\gamma _n\) be standard Gaussian measure on \(\mathbb R^n\). For a measurable \(A\subseteq \mathbb R^n\), let \(u_\theta (x)=\mathbb E_Y1_A(\cos \theta \, x+\sin \theta \, Y)\) with \(Y\sim \gamma _n\), and put \(R_A(\theta )=\Pr (1_A(X)\ne 1_A(\cos \theta \, X+\sin \theta \, Y))\) for independent \(X,Y\sim \gamma _n\). For every \(\varepsilon \gt 0\) there exists \(C\gt 0\) such that \(\int \overline I(u_\theta (x))\, d\gamma _n(x)\le \varepsilon +CR_A(\theta )\) for every real \(\theta \).

Lemma 249.3 Vanishing integral profile of averaged indicators
✓

Let \(\Phi ,\varphi \) be the standard Gaussian distribution function and density, and let \(\overline I(p)=\varphi (\Phi ^{-1}(p))\) for \(0\lt p\lt 1\), with \(\overline I(p)=0\) elsewhere. Let \(\gamma _n\) be standard Gaussian measure on \(\mathbb R^n\). For a measurable \(A\subseteq \mathbb R^n\), let \(u_\theta (x)=\mathbb E_Y1_A(\cos \theta \, x+\sin \theta \, Y)\) with \(Y\sim \gamma _n\), and put \(R_A(\theta )=\Pr (1_A(X)\ne 1_A(\cos \theta \, X+\sin \theta \, Y))\) for independent \(X,Y\sim \gamma _n\). Then \(\int \overline I(u_\theta (x))\, d\gamma _n(x)\to 0\) as \(\theta \to 0\) through real values.