Cartan projections of fiber products and non quasi-isometric embeddings

Fuente: arXiv
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Main Author: Tsouvalas, Konstantinos
Format: Preprint
Published: 2022
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author Tsouvalas, Konstantinos
author_facet Tsouvalas, Konstantinos
contents Let $Γ$ be a finitely generated group and $N$ be a normal subgroup of $Γ$. The fiber product of $Γ$ with respect to $N$ is the subgroup $Γ\times_N Γ=\{(γ, γw): γ\in Γ, w \in N\}$ of the direct product $Γ\times Γ$. For every representation $ρ:Γ\times_N Γ\rightarrow \mathsf{GL}_d(k)$, where $k$ is a local field, we establish upper bounds for the norm of the Cartan projection of $ρ$ in terms of a fixed word length function on $Γ$. As an application, we exhibit examples of finitely generated and finitely presented fiber products $P=Γ\times_N Γ$, where $Γ$ is linear and Gromov hyperbolic, such that $P$ does not admit linear representations which are quasi-isometric embeddings.
format Preprint
id arxiv_https___arxiv_org_abs_2205_11960
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Cartan projections of fiber products and non quasi-isometric embeddings
Tsouvalas, Konstantinos
Group Theory
Let $Γ$ be a finitely generated group and $N$ be a normal subgroup of $Γ$. The fiber product of $Γ$ with respect to $N$ is the subgroup $Γ\times_N Γ=\{(γ, γw): γ\in Γ, w \in N\}$ of the direct product $Γ\times Γ$. For every representation $ρ:Γ\times_N Γ\rightarrow \mathsf{GL}_d(k)$, where $k$ is a local field, we establish upper bounds for the norm of the Cartan projection of $ρ$ in terms of a fixed word length function on $Γ$. As an application, we exhibit examples of finitely generated and finitely presented fiber products $P=Γ\times_N Γ$, where $Γ$ is linear and Gromov hyperbolic, such that $P$ does not admit linear representations which are quasi-isometric embeddings.
title Cartan projections of fiber products and non quasi-isometric embeddings
topic Group Theory
url https://arxiv.org/abs/2205.11960