TCSLib

226 Boolean Analysis — Boolean Blocks

226.1 Overview

Finite coordinate reindexing and currying preserve product measures. The Boolean Bobkov inequality therefore holds for arbitrary finite coordinate sets and for arrays of bits.

226.2 Declarations

Lemma 226.1 Currying preserves finite product laws
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Let \(I,J,B\) be finite sets, let \(B\) carry a measurable structure with measurable singletons, and let \(\mu _{ij}\) be sigma-finite measures on \(B\). The bijection \(B^{I\times J}\to (B^J)^I\) sending \(x\) to the array \(i\mapsto (j\mapsto x(i,j))\) pushes \(\bigotimes _{(i,j)}\mu _{ij}\) to \(\bigotimes _i\bigotimes _j\mu _{ij}\).

Lemma 226.2 Bobkov inequality for finite coordinates
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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 \(I\) be finite and \(f:\{ 0,1\} ^I\to [0,1]\). Under the independent uniform bit law, \(\overline I(\mathbb E f)\le \mathbb E\sqrt{\overline I(f)^2+\sum _{i\in I}(D_i f)^2}\), where \(D_i f(x)=(f(x^{i\leftarrow 0})-f(x^{i\leftarrow 1}))/2\).

Lemma 226.3 Bobkov inequality for Boolean arrays
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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 \(I,J\) be finite and \(f:\{ 0,1\} ^{I\times J}\to [0,1]\). Under independent uniform bits, \(\overline I(\mathbb E f)\le \mathbb E\sqrt{\overline I(f)^2+\sum _{i\in I}\sum _{j\in J}(D_{ij}f)^2}\), where \(D_{ij}f(x)=(f(x^{ij\leftarrow 0})-f(x^{ij\leftarrow 1}))/2\).