On the universality of fluctuations for the cover time

Fuente: arXiv
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Main Authors: Berestycki, Nathanaël, Hermon, Jonathan, Teyssier, Lucas
Format: Preprint
Published: 2022
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author Berestycki, Nathanaël
Hermon, Jonathan
Teyssier, Lucas
author_facet Berestycki, Nathanaël
Hermon, Jonathan
Teyssier, Lucas
contents We consider random walks on finite vertex-transitive graphs $Γ$ of bounded degree. We find a simple geometric condition which characterises the cover time fluctuations: the suitably normalised cover time converges to a standard Gumbel variable if and only if $\mathrm{Diam}(Γ)^2 = o(n/\log n)$, where $n = |Γ|$. We prove that this condition is furthermore equivalent to the decorrelation of the uncovered set. The arguments rely on recent breakthroughs by Tessera and Tointon on finitary versions of Gromov's theorem on groups of polynomial growth, which we leverage into strong heat kernel bounds, and refined quantitative estimates on Aldous and Brown's exponential approximation of hitting times, which are of independent interest.
format Preprint
id arxiv_https___arxiv_org_abs_2202_02255
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle On the universality of fluctuations for the cover time
Berestycki, Nathanaël
Hermon, Jonathan
Teyssier, Lucas
Probability
Group Theory
Metric Geometry
We consider random walks on finite vertex-transitive graphs $Γ$ of bounded degree. We find a simple geometric condition which characterises the cover time fluctuations: the suitably normalised cover time converges to a standard Gumbel variable if and only if $\mathrm{Diam}(Γ)^2 = o(n/\log n)$, where $n = |Γ|$. We prove that this condition is furthermore equivalent to the decorrelation of the uncovered set. The arguments rely on recent breakthroughs by Tessera and Tointon on finitary versions of Gromov's theorem on groups of polynomial growth, which we leverage into strong heat kernel bounds, and refined quantitative estimates on Aldous and Brown's exponential approximation of hitting times, which are of independent interest.
title On the universality of fluctuations for the cover time
topic Probability
Group Theory
Metric Geometry
url https://arxiv.org/abs/2202.02255