Medvedev degrees of subshifts on groups

Fuente: arXiv
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Main Authors: Barbieri, Sebastián, Carrasco-Vargas, Nicanor
Format: Preprint
Published: 2024
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author Barbieri, Sebastián
Carrasco-Vargas, Nicanor
author_facet Barbieri, Sebastián
Carrasco-Vargas, Nicanor
contents The Medvedev degree of a subshift is a dynamical invariant of computable origin that can be used to compare the complexity of subshifts that contain only uncomputable configurations. We develop theory to describe how these degrees can be transferred from one group to another through algebraic and geometric relations, such as quotients, subgroups, translation-like actions and quasi-isometries. We use the aforementioned tools to study the possible values taken by this invariant on subshifts of finite type on some finitely generated groups. We obtain a full classification for some classes, such as virtually polycyclic groups and branch groups with decidable word problem. We also show that all groups which are quasi-isometric to the hyperbolic plane admit SFTs with nonzero Medvedev degree. Furthermore, we provide a classification of the degrees of sofic subshifts for several classes of groups.
format Preprint
id arxiv_https___arxiv_org_abs_2406_12777
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Medvedev degrees of subshifts on groups
Barbieri, Sebastián
Carrasco-Vargas, Nicanor
Dynamical Systems
Group Theory
Logic
37B10, 03D78, 20F10
The Medvedev degree of a subshift is a dynamical invariant of computable origin that can be used to compare the complexity of subshifts that contain only uncomputable configurations. We develop theory to describe how these degrees can be transferred from one group to another through algebraic and geometric relations, such as quotients, subgroups, translation-like actions and quasi-isometries. We use the aforementioned tools to study the possible values taken by this invariant on subshifts of finite type on some finitely generated groups. We obtain a full classification for some classes, such as virtually polycyclic groups and branch groups with decidable word problem. We also show that all groups which are quasi-isometric to the hyperbolic plane admit SFTs with nonzero Medvedev degree. Furthermore, we provide a classification of the degrees of sofic subshifts for several classes of groups.
title Medvedev degrees of subshifts on groups
topic Dynamical Systems
Group Theory
Logic
37B10, 03D78, 20F10
url https://arxiv.org/abs/2406.12777