On the kernel of actions on asymptotic cones

Fuente: arXiv
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Autori principali: Baik, Hyungryul, Jang, Wonyong
Natura: Preprint
Pubblicazione: 2024
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author Baik, Hyungryul
Jang, Wonyong
author_facet Baik, Hyungryul
Jang, Wonyong
contents Any finitely generated group $G$ acts on its asymptotic cones in natural ways. The purpose of this paper is to calculate the kernel of such actions. First, we show that when $G$ is acylindrically hyperbolic, the kernel of the natural action on every asymptotic cone coincides with the unique maximal finite normal subgroup $K(G)$ of $G$. Secondly, we use this equivalence to interpret the kernel of the actions on asymptotic cones as the kernel of the actions on many spaces at "infinity". For instance, if $G \curvearrowright M$ is a non-elementary convergence group, then we show that the kernel of actions on the limit set $L(G)$ coincides with the kernel of the action on asymptotic cones. Similar results can also be established for the non-trivial Floyd boundary and the $\mathrm{CAT}(0)$ groups with the visual boundary, contracting boundary, and sublinearly Morse boundary. Additionally, the results are extended to another action on asymptotic cones, called Paulin's construction. In the last section, we calculate the kernel on asymptotic cones for various groups, and as an application, we show that the cardinality of the kernel can determine whether the group admits non-elementary action under some mild assumptions.
format Preprint
id arxiv_https___arxiv_org_abs_2402_09969
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the kernel of actions on asymptotic cones
Baik, Hyungryul
Jang, Wonyong
Group Theory
20F65, 20F67 (Primary) 20F69, 51F30 (Secondary)
Any finitely generated group $G$ acts on its asymptotic cones in natural ways. The purpose of this paper is to calculate the kernel of such actions. First, we show that when $G$ is acylindrically hyperbolic, the kernel of the natural action on every asymptotic cone coincides with the unique maximal finite normal subgroup $K(G)$ of $G$. Secondly, we use this equivalence to interpret the kernel of the actions on asymptotic cones as the kernel of the actions on many spaces at "infinity". For instance, if $G \curvearrowright M$ is a non-elementary convergence group, then we show that the kernel of actions on the limit set $L(G)$ coincides with the kernel of the action on asymptotic cones. Similar results can also be established for the non-trivial Floyd boundary and the $\mathrm{CAT}(0)$ groups with the visual boundary, contracting boundary, and sublinearly Morse boundary. Additionally, the results are extended to another action on asymptotic cones, called Paulin's construction. In the last section, we calculate the kernel on asymptotic cones for various groups, and as an application, we show that the cardinality of the kernel can determine whether the group admits non-elementary action under some mild assumptions.
title On the kernel of actions on asymptotic cones
topic Group Theory
20F65, 20F67 (Primary) 20F69, 51F30 (Secondary)
url https://arxiv.org/abs/2402.09969