English

Behaviors of entropy on finitely generated groups

Group Theory 2013-12-17 v3 Probability

Abstract

A variety of behaviors of entropy functions of random walks on finitely generated groups is presented, showing that for any 12αβ1\frac{1}{2}\leq \alpha\leq\beta\leq1, there is a group Γ\Gamma with measure μ\mu equidistributed on a finite generating set such that lim inflogHΓ,μ(n)logn=α,lim suplogHΓ,μ(n)logn=β.\liminf\frac{\log H_{\Gamma ,\mu}(n)}{\log n}=\alpha ,\qquad \limsup \frac{\log H_{\Gamma ,\mu}(n)}{\log n}=\beta . The groups involved are finitely generated subgroups of the group of automorphisms of an extended rooted tree. The return probability and the drift of a simple random walk YnY_n on such groups are also evaluated, providing an example of group with return probability satisfying lim infloglogP(Yn=Γ1)logn=13,lim suploglogP(Yn=Γ1)logn=1\liminf\frac{{\log}|{\log P}(Y_n=_{\Gamma}1)|}{\log n}=\frac{1}{3},\qquad \limsup\frac{{\log}|{\log P}(Y_n=_{\Gamma}1)|}{\log n}=1 and drift satisfying lim inflogEYnlogn=12,lim suplogEYnlogn=1.\liminf\frac{\log {\mathbb{E}}\|Y_n\|}{\log n}=\frac{1}{2},\qquad \limsup\frac{\log {\mathbb{E}}\|Y_n\|}{\log n}=1.

Keywords

Cite

@article{arxiv.1110.5099,
  title  = {Behaviors of entropy on finitely generated groups},
  author = {Jérémie Brieussel},
  journal= {arXiv preprint arXiv:1110.5099},
  year   = {2013}
}

Comments

Published in at http://dx.doi.org/10.1214/12-AOP761 the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org)