The Defining Characteristic Case of the Representations of $\mathrm{GL}_{n}$ and $\mathrm{SL}_{n}$ over Principal Ideal Local Rings

Fuente: arXiv
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Autore principale: Monteiro, Nariel
Natura: Preprint
Pubblicazione: 2024
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author Monteiro, Nariel
author_facet Monteiro, Nariel
contents Let $W_{r}(\mathbb{F}_{q})$ be the ring of Witt vectors of length $r$ with residue field $\mathbb{F}_{q}$ of characteristic $p$. In this paper, we study the defining characteristic case of the representations of $\mathrm{GL}_{n}$ and $\mathrm{SL}_{n}$ over the principal ideal local rings $W_{r}(\mathbb{F}_{q})$ and $\mathbb{F}_{q}[t]/t^{r}$. Let ${\mathbf{G}}$ be either $\mathrm{GL}_{n}$ or $\mathrm{SL}_{n}$ and $F$ a perfect field of characteristic $p$, we prove that for most $p$ the group algebras $F[{\mathbf{G}}(W_{r}(\mathbb{F}_{q}))]$ and $F[{\mathbf{G}}(\mathbb{F}_{q}[t]/t^{r})]$ are not stably equivalent of Morita type. Thus, the group algebras $F[{\mathbf{G}}(W_{r}(\mathbb{F}_{q}))]$ and $F[{\mathbf{G}}(\mathbb{F}_{q}[t]/t^{r})]$ are not isomorphic in the defining characteristic case.
format Preprint
id arxiv_https___arxiv_org_abs_2409_17982
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Defining Characteristic Case of the Representations of $\mathrm{GL}_{n}$ and $\mathrm{SL}_{n}$ over Principal Ideal Local Rings
Monteiro, Nariel
Representation Theory
Group Theory
20C20, 20G05
Let $W_{r}(\mathbb{F}_{q})$ be the ring of Witt vectors of length $r$ with residue field $\mathbb{F}_{q}$ of characteristic $p$. In this paper, we study the defining characteristic case of the representations of $\mathrm{GL}_{n}$ and $\mathrm{SL}_{n}$ over the principal ideal local rings $W_{r}(\mathbb{F}_{q})$ and $\mathbb{F}_{q}[t]/t^{r}$. Let ${\mathbf{G}}$ be either $\mathrm{GL}_{n}$ or $\mathrm{SL}_{n}$ and $F$ a perfect field of characteristic $p$, we prove that for most $p$ the group algebras $F[{\mathbf{G}}(W_{r}(\mathbb{F}_{q}))]$ and $F[{\mathbf{G}}(\mathbb{F}_{q}[t]/t^{r})]$ are not stably equivalent of Morita type. Thus, the group algebras $F[{\mathbf{G}}(W_{r}(\mathbb{F}_{q}))]$ and $F[{\mathbf{G}}(\mathbb{F}_{q}[t]/t^{r})]$ are not isomorphic in the defining characteristic case.
title The Defining Characteristic Case of the Representations of $\mathrm{GL}_{n}$ and $\mathrm{SL}_{n}$ over Principal Ideal Local Rings
topic Representation Theory
Group Theory
20C20, 20G05
url https://arxiv.org/abs/2409.17982