$τ$-Tilting finiteness of group algebras over generalized symmetric groups

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1. Verfasser: Hiramae, Naoya
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Veröffentlicht: 2024
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author Hiramae, Naoya
author_facet Hiramae, Naoya
contents In this paper, we show that weakly symmetric $τ$-tilting finite algebras have positive definite Cartan matrices, which implies that we can prove $τ$-tilting infiniteness of weakly symmetric algebras by calculating their Cartan matrices. Similarly, we obtain the condition on Cartan matrices that selfinjective algebras are $τ$-tilting infinite. By applying this result, we show that a group algebra of $(\mathbb{Z}/p^l\mathbb{Z})^n\rtimes H$ is $τ$-tilting infinite when $p^l\geq n$ and $\#\mathrm{IBr}\,H\geq\min\{p,3\}$, where $p>0$ is the characteristic of the ground field, $H$ is a subgroup of the symmetric group $\mathfrak{S}_n$ of degree $n$, the action of $H$ permutes the entries of $(\mathbb{Z}/p^l\mathbb{Z})^n$, and $\mathrm{IBr}\,H$ denotes the set of irreducible $p$-Brauer characters of $H$. Moreover, we show that under the assumption that $p^l\geq n$ and $H$ is a $p'$-subgroup of $\mathfrak{S}_n$, $τ$-tilting finiteness of a group algebra of a group $(\mathbb{Z}/p^l\mathbb{Z})^n\rtimes H$ is determined by its $p$-hyperfocal subgroup.
format Preprint
id arxiv_https___arxiv_org_abs_2405_10726
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle $τ$-Tilting finiteness of group algebras over generalized symmetric groups
Hiramae, Naoya
Representation Theory
Group Theory
Rings and Algebras
16G10, 20C20
In this paper, we show that weakly symmetric $τ$-tilting finite algebras have positive definite Cartan matrices, which implies that we can prove $τ$-tilting infiniteness of weakly symmetric algebras by calculating their Cartan matrices. Similarly, we obtain the condition on Cartan matrices that selfinjective algebras are $τ$-tilting infinite. By applying this result, we show that a group algebra of $(\mathbb{Z}/p^l\mathbb{Z})^n\rtimes H$ is $τ$-tilting infinite when $p^l\geq n$ and $\#\mathrm{IBr}\,H\geq\min\{p,3\}$, where $p>0$ is the characteristic of the ground field, $H$ is a subgroup of the symmetric group $\mathfrak{S}_n$ of degree $n$, the action of $H$ permutes the entries of $(\mathbb{Z}/p^l\mathbb{Z})^n$, and $\mathrm{IBr}\,H$ denotes the set of irreducible $p$-Brauer characters of $H$. Moreover, we show that under the assumption that $p^l\geq n$ and $H$ is a $p'$-subgroup of $\mathfrak{S}_n$, $τ$-tilting finiteness of a group algebra of a group $(\mathbb{Z}/p^l\mathbb{Z})^n\rtimes H$ is determined by its $p$-hyperfocal subgroup.
title $τ$-Tilting finiteness of group algebras over generalized symmetric groups
topic Representation Theory
Group Theory
Rings and Algebras
16G10, 20C20
url https://arxiv.org/abs/2405.10726