Sylvester domains and pro-$p$ groups

Fuente: arXiv
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Hauptverfasser: Jaikin-Zapirain, Andrei, Souza, Henrique
Format: Preprint
Veröffentlicht: 2024
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author Jaikin-Zapirain, Andrei
Souza, Henrique
author_facet Jaikin-Zapirain, Andrei
Souza, Henrique
contents Let $G$ be a finitely generated torsion-free pro-$p$ group containing an open free-by-$\mathbb{Z}_p$ pro-$p$ subgroup. We show that the completed group algebra of $G$ over $\mathbb{F}_p$ is a Sylvester domain. Moreover the inner rank of a matrix $A$ over this completed group algebra can be calculated by approximation by ranks corresponding to finite quotients of $G$, that is, if $G=G_1>G_2>\ldots$ is a chain of normal open subgroups of $G$ with trivial intersection and $A_i$ is the matrix over $\mathbb{F}_p[G/G_i]$ obtained from the matrix $A$ by applying the natural homomorphism induced from $G \to G/G_i$, then the inner rank of $A$ equals $\lim_{i\to \infty} \frac{\operatorname{rk}_{\mathbb{F}_p} (A_i)}{|G:G_i|}$. As a consequence, we obtain a particular case of the mod $p$ Lück approximation for abstract finitely generated subgroups of free-by-$\mathbb{Z}_p$ pro-$p$ groups.
format Preprint
id arxiv_https___arxiv_org_abs_2402_14130
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Sylvester domains and pro-$p$ groups
Jaikin-Zapirain, Andrei
Souza, Henrique
Group Theory
Rings and Algebras
20E18, 20E22, 16S35, 16S85
Let $G$ be a finitely generated torsion-free pro-$p$ group containing an open free-by-$\mathbb{Z}_p$ pro-$p$ subgroup. We show that the completed group algebra of $G$ over $\mathbb{F}_p$ is a Sylvester domain. Moreover the inner rank of a matrix $A$ over this completed group algebra can be calculated by approximation by ranks corresponding to finite quotients of $G$, that is, if $G=G_1>G_2>\ldots$ is a chain of normal open subgroups of $G$ with trivial intersection and $A_i$ is the matrix over $\mathbb{F}_p[G/G_i]$ obtained from the matrix $A$ by applying the natural homomorphism induced from $G \to G/G_i$, then the inner rank of $A$ equals $\lim_{i\to \infty} \frac{\operatorname{rk}_{\mathbb{F}_p} (A_i)}{|G:G_i|}$. As a consequence, we obtain a particular case of the mod $p$ Lück approximation for abstract finitely generated subgroups of free-by-$\mathbb{Z}_p$ pro-$p$ groups.
title Sylvester domains and pro-$p$ groups
topic Group Theory
Rings and Algebras
20E18, 20E22, 16S35, 16S85
url https://arxiv.org/abs/2402.14130