Large Deviations of Cover Time of Tori in Dimensions $d\geq 3$

Fuente: arXiv
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Main Authors: Li, Xinyi, Shi, Jialu, Xu, Qiheng
Format: Preprint
Published: 2024
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author Li, Xinyi
Shi, Jialu
Xu, Qiheng
author_facet Li, Xinyi
Shi, Jialu
Xu, Qiheng
contents We consider large deviations of the cover time of the discrete torus $(\mathbb{Z}/N\mathbb{Z})^d$, $d \geq 3$ by simple random walk. We prove a lower bound on the probability that the cover time is smaller than $γ\in (0,1)$ times its expected value, with exponents matching the upper bound from [Goodman-den Hollander, Probab. Theory Related Fields (2014)] and [Comets-Gallesco-Popov-Vachkovskaia, Electron. J. Probab. (2013)]. Moreover, we derive sharp asymptotics for $γ\in (\frac{d+2}{2d},1)$. The strong coupling of the random walk on the torus and random interlacements developed in a recent work [Prévost-Rodriguez-Sousi, arXiv:2309.03192] serves as an important ingredient in the proofs.
format Preprint
id arxiv_https___arxiv_org_abs_2411_16398
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Large Deviations of Cover Time of Tori in Dimensions $d\geq 3$
Li, Xinyi
Shi, Jialu
Xu, Qiheng
Probability
05C81, 60F10, 60G70
We consider large deviations of the cover time of the discrete torus $(\mathbb{Z}/N\mathbb{Z})^d$, $d \geq 3$ by simple random walk. We prove a lower bound on the probability that the cover time is smaller than $γ\in (0,1)$ times its expected value, with exponents matching the upper bound from [Goodman-den Hollander, Probab. Theory Related Fields (2014)] and [Comets-Gallesco-Popov-Vachkovskaia, Electron. J. Probab. (2013)]. Moreover, we derive sharp asymptotics for $γ\in (\frac{d+2}{2d},1)$. The strong coupling of the random walk on the torus and random interlacements developed in a recent work [Prévost-Rodriguez-Sousi, arXiv:2309.03192] serves as an important ingredient in the proofs.
title Large Deviations of Cover Time of Tori in Dimensions $d\geq 3$
topic Probability
05C81, 60F10, 60G70
url https://arxiv.org/abs/2411.16398