Shifted Composition II: Shift Harnack Inequalities and Curvature Upper Bounds

Fuente: arXiv
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Autori principali: Altschuler, Jason M., Chewi, Sinho
Natura: Preprint
Pubblicazione: 2023
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author Altschuler, Jason M.
Chewi, Sinho
author_facet Altschuler, Jason M.
Chewi, Sinho
contents We apply the shifted composition rule -- an information-theoretic principle introduced in our earlier work [AC23] -- to establish shift Harnack inequalities for the Langevin diffusion. We obtain sharp constants for these inequalities for the first time, allowing us to investigate their relationship with other properties of the diffusion. Namely, we show that they are equivalent to a sharp "local gradient-entropy" bound, and that they imply curvature upper bounds in a compelling reflection of the Bakry-Emery theory of curvature lower bounds. Finally, we show that the local gradient-entropy inequality implies optimal concentration of the score, a.k.a. the logarithmic gradient of the density.
format Preprint
id arxiv_https___arxiv_org_abs_2401_00071
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Shifted Composition II: Shift Harnack Inequalities and Curvature Upper Bounds
Altschuler, Jason M.
Chewi, Sinho
Probability
Information Theory
Analysis of PDEs
Functional Analysis
We apply the shifted composition rule -- an information-theoretic principle introduced in our earlier work [AC23] -- to establish shift Harnack inequalities for the Langevin diffusion. We obtain sharp constants for these inequalities for the first time, allowing us to investigate their relationship with other properties of the diffusion. Namely, we show that they are equivalent to a sharp "local gradient-entropy" bound, and that they imply curvature upper bounds in a compelling reflection of the Bakry-Emery theory of curvature lower bounds. Finally, we show that the local gradient-entropy inequality implies optimal concentration of the score, a.k.a. the logarithmic gradient of the density.
title Shifted Composition II: Shift Harnack Inequalities and Curvature Upper Bounds
topic Probability
Information Theory
Analysis of PDEs
Functional Analysis
url https://arxiv.org/abs/2401.00071