Finite groups of untwisted outer automorphisms of RAAGs

Fuente: arXiv
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Main Authors: Bregman, Corey, Charney, Ruth, Vogtmann, Karen
Format: Preprint
Published: 2023
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author Bregman, Corey
Charney, Ruth
Vogtmann, Karen
author_facet Bregman, Corey
Charney, Ruth
Vogtmann, Karen
contents For any right-angled Artin group $A_Γ$, Charney--Stambaugh--Vogtmann showed that the subgroup $U^0(A_Γ) \leq\text{Out}(A_Γ)$ generated by Whitehead automorphisms and inversions acts properly and cocompactly on a contractible space $K_Γ$. In the present paper we show that any finite subgroup of $U^0(A_Γ)$ fixes a point of $K_Γ$. This generalizes the fact that any finite subgroup of $\text{Out}(F_n)$ fixes a point of Outer Space, and implies that there are only finitely many conjugacy classes of finite subgroups in $U^0(A_Γ)$.
format Preprint
id arxiv_https___arxiv_org_abs_2308_09222
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Finite groups of untwisted outer automorphisms of RAAGs
Bregman, Corey
Charney, Ruth
Vogtmann, Karen
Group Theory
Geometric Topology
20F65, 20F28, 20F36
For any right-angled Artin group $A_Γ$, Charney--Stambaugh--Vogtmann showed that the subgroup $U^0(A_Γ) \leq\text{Out}(A_Γ)$ generated by Whitehead automorphisms and inversions acts properly and cocompactly on a contractible space $K_Γ$. In the present paper we show that any finite subgroup of $U^0(A_Γ)$ fixes a point of $K_Γ$. This generalizes the fact that any finite subgroup of $\text{Out}(F_n)$ fixes a point of Outer Space, and implies that there are only finitely many conjugacy classes of finite subgroups in $U^0(A_Γ)$.
title Finite groups of untwisted outer automorphisms of RAAGs
topic Group Theory
Geometric Topology
20F65, 20F28, 20F36
url https://arxiv.org/abs/2308.09222