Restricted Permutations and Permanents of Infinite Amenable Groups

Fuente: arXiv
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Autores principales: Li, Hanfeng, Schmidt, Klaus
Formato: Preprint
Publicado: 2025
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author Li, Hanfeng
Schmidt, Klaus
author_facet Li, Hanfeng
Schmidt, Klaus
contents Let $Γ$ be an infinite discrete group and $\mathsf{A}\subset Γ$ a nonempty finite subset. The set of permutations $σ$ of $Γ$ such that $s^{-1}σ(s)\in \mathsf{A}$ for every $s\in Γ$ can be identified with a shift of finite type $X_\mathsf{A}\subset \mathsf{A}^Γ$ over $Γ$. In this paper we study dynamical properties of such shift spaces, like invariant probability measures, topological entropy, and topological pressure, under the hypothesis that $Γ$ is amenable. In this case the topological entropy $\textrm{h}_{\textrm{top}}(X_\mathsf{A})$ can be expressed as logarithmic growth rate of permanents of certain finite (0,1)-matrices associated with right Følner sequences in $Γ$. Motivated by the difficulty of computing such permanents we introduce the notion of the permanent $\textrm{per}(f)$ for nonnegative elements $f$ in the real group ring $\mathbb{R}Γ$ of $Γ$ whose support is the alphabet $\mathsf{A}$ of the shift space $X_\mathsf{A}$, and compare, for arbitrary $f \in \mathbb{R}Γ$, the Fuglede-Kadison determinant $\textrm{det} _\textrm{FK}(f)$ with the permanent $\textrm{per}(|f|)$ of the absolute value $|f|$ of $f$. Although this approach is effective in only few examples, discussed below, it is interesting from a conceptual point of view that the permanent $\textrm{per}(f)$ of a nonnegative element $f\in \mathbb{R}Γ$ can be viewed as topological pressure of the restricted-permutation shift space $X_\mathsf{A}$ associated with the function $\log f$ on the alphabet $\mathsf{A}=\textrm{supp}(f)$ of $X_\mathsf{A}$.
format Preprint
id arxiv_https___arxiv_org_abs_2501_05261
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Restricted Permutations and Permanents of Infinite Amenable Groups
Li, Hanfeng
Schmidt, Klaus
Dynamical Systems
37A15 (Primary) 37A20, 37A35, 37B10, 37B51 (Secondary)
Let $Γ$ be an infinite discrete group and $\mathsf{A}\subset Γ$ a nonempty finite subset. The set of permutations $σ$ of $Γ$ such that $s^{-1}σ(s)\in \mathsf{A}$ for every $s\in Γ$ can be identified with a shift of finite type $X_\mathsf{A}\subset \mathsf{A}^Γ$ over $Γ$. In this paper we study dynamical properties of such shift spaces, like invariant probability measures, topological entropy, and topological pressure, under the hypothesis that $Γ$ is amenable. In this case the topological entropy $\textrm{h}_{\textrm{top}}(X_\mathsf{A})$ can be expressed as logarithmic growth rate of permanents of certain finite (0,1)-matrices associated with right Følner sequences in $Γ$. Motivated by the difficulty of computing such permanents we introduce the notion of the permanent $\textrm{per}(f)$ for nonnegative elements $f$ in the real group ring $\mathbb{R}Γ$ of $Γ$ whose support is the alphabet $\mathsf{A}$ of the shift space $X_\mathsf{A}$, and compare, for arbitrary $f \in \mathbb{R}Γ$, the Fuglede-Kadison determinant $\textrm{det} _\textrm{FK}(f)$ with the permanent $\textrm{per}(|f|)$ of the absolute value $|f|$ of $f$. Although this approach is effective in only few examples, discussed below, it is interesting from a conceptual point of view that the permanent $\textrm{per}(f)$ of a nonnegative element $f\in \mathbb{R}Γ$ can be viewed as topological pressure of the restricted-permutation shift space $X_\mathsf{A}$ associated with the function $\log f$ on the alphabet $\mathsf{A}=\textrm{supp}(f)$ of $X_\mathsf{A}$.
title Restricted Permutations and Permanents of Infinite Amenable Groups
topic Dynamical Systems
37A15 (Primary) 37A20, 37A35, 37B10, 37B51 (Secondary)
url https://arxiv.org/abs/2501.05261