Cutoff for random walks on dihedral groups

Fuente: arXiv
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Main Authors: Huang, Xiangying, Rao, Renyu
Format: Preprint
Published: 2025
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_version_ 1866915571348537344
author Huang, Xiangying
Rao, Renyu
author_facet Huang, Xiangying
Rao, Renyu
contents We study the random walk on a finite dihedral group $G$ driven by the uniform measure on $k$ independently and uniformly chosen elements. We show that the walk exhibits cutoff with high probability throughout nearly the entire regime $1 \ll \log k \ll \log |G|$, and determine the precise cutoff time. Interestingly, this mixing time differs from the entropic time that characterizes cutoff behavior for random walks on Abelian groups. When $k \gg \log|G|$ and $\log k \ll \log|G|$, cutoff occurs with high probability on random Cayley graphs of virtually Abelian groups. The analysis develops techniques for obtaining sharper entropic estimates of an auxiliary process on high-dimensional lattices with dependent coordinates, which may also prove useful for related models in broader contexts.
format Preprint
id arxiv_https___arxiv_org_abs_2510_19942
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Cutoff for random walks on dihedral groups
Huang, Xiangying
Rao, Renyu
Probability
05C81, 60B15, 60J27
We study the random walk on a finite dihedral group $G$ driven by the uniform measure on $k$ independently and uniformly chosen elements. We show that the walk exhibits cutoff with high probability throughout nearly the entire regime $1 \ll \log k \ll \log |G|$, and determine the precise cutoff time. Interestingly, this mixing time differs from the entropic time that characterizes cutoff behavior for random walks on Abelian groups. When $k \gg \log|G|$ and $\log k \ll \log|G|$, cutoff occurs with high probability on random Cayley graphs of virtually Abelian groups. The analysis develops techniques for obtaining sharper entropic estimates of an auxiliary process on high-dimensional lattices with dependent coordinates, which may also prove useful for related models in broader contexts.
title Cutoff for random walks on dihedral groups
topic Probability
05C81, 60B15, 60J27
url https://arxiv.org/abs/2510.19942