Functional Inequalities and Random Walks on Increasing Subsets of the Hypercube

Fuente: arXiv
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Main Authors: Chang, Fan, Sun, Guowei, Yu, Lei
Format: Preprint
Published: 2025
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author Chang, Fan
Sun, Guowei
Yu, Lei
author_facet Chang, Fan
Sun, Guowei
Yu, Lei
contents Motivated by random walks on subsets of the hypercube, we prove two discrete functional inequalities on the hypercube. First, we give a short, elementary proof of the Poincaré inequality on increasing subsets of the cube recently established by Fei and Ferreira Pinto Jr, which yields an $O(n^2)$ upper bound on the mixing time of censored random walks, improving upon previous bounds. Second, adapting Samorodnitsky's induction method to the $p$-biased setting, we establish a sharp $p$-biased edge-isoperimetric inequality for real-valued increasing functions, which recovers the classic biased edge-isoperimetric inequality for increasing sets and identifies increasing subcubes as the extremizers. This result also admits a probabilistic interpretation in terms of maximizing the mean first exit time of biased random walks.
format Preprint
id arxiv_https___arxiv_org_abs_2506_09852
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Functional Inequalities and Random Walks on Increasing Subsets of the Hypercube
Chang, Fan
Sun, Guowei
Yu, Lei
Combinatorics
Probability
06E30, 05C81, 60C05, 60G50
Motivated by random walks on subsets of the hypercube, we prove two discrete functional inequalities on the hypercube. First, we give a short, elementary proof of the Poincaré inequality on increasing subsets of the cube recently established by Fei and Ferreira Pinto Jr, which yields an $O(n^2)$ upper bound on the mixing time of censored random walks, improving upon previous bounds. Second, adapting Samorodnitsky's induction method to the $p$-biased setting, we establish a sharp $p$-biased edge-isoperimetric inequality for real-valued increasing functions, which recovers the classic biased edge-isoperimetric inequality for increasing sets and identifies increasing subcubes as the extremizers. This result also admits a probabilistic interpretation in terms of maximizing the mean first exit time of biased random walks.
title Functional Inequalities and Random Walks on Increasing Subsets of the Hypercube
topic Combinatorics
Probability
06E30, 05C81, 60C05, 60G50
url https://arxiv.org/abs/2506.09852