On exterior powers of reflection representations, II

Fuente: arXiv
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Autore principale: Hu, Hongsheng
Natura: Preprint
Pubblicazione: 2024
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author Hu, Hongsheng
author_facet Hu, Hongsheng
contents Let $W$ be a group endowed with a finite set $S$ of generators. A representation $(V,ρ)$ of $W$ is called a reflection representation of $(W,S)$ if $ρ(s)$ is a (generalized) reflection on $V$ for each generator $s \in S$. In this paper, we prove that for any irreducible reflection representation $V$, all the exterior powers $\bigwedge ^d V$, $d = 0, 1, \dots, \dim V$, are irreducible $W$-modules, and they are non-isomorphic to each other. This extends a theorem of R. Steinberg which is stated for Euclidean reflection groups. Moreover, we prove that the exterior powers (except for the 0th and the highest power) of two non-isomorphic reflection representations always give non-isomorphic $W$-modules. This allows us to construct numerous pairwise non-isomorphic irreducible representations for such groups, especially for Coxeter groups.
format Preprint
id arxiv_https___arxiv_org_abs_2401_08215
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On exterior powers of reflection representations, II
Hu, Hongsheng
Representation Theory
Combinatorics
Group Theory
Rings and Algebras
15A75, 05E10, 20C15, 20F55, 51F15
Let $W$ be a group endowed with a finite set $S$ of generators. A representation $(V,ρ)$ of $W$ is called a reflection representation of $(W,S)$ if $ρ(s)$ is a (generalized) reflection on $V$ for each generator $s \in S$. In this paper, we prove that for any irreducible reflection representation $V$, all the exterior powers $\bigwedge ^d V$, $d = 0, 1, \dots, \dim V$, are irreducible $W$-modules, and they are non-isomorphic to each other. This extends a theorem of R. Steinberg which is stated for Euclidean reflection groups. Moreover, we prove that the exterior powers (except for the 0th and the highest power) of two non-isomorphic reflection representations always give non-isomorphic $W$-modules. This allows us to construct numerous pairwise non-isomorphic irreducible representations for such groups, especially for Coxeter groups.
title On exterior powers of reflection representations, II
topic Representation Theory
Combinatorics
Group Theory
Rings and Algebras
15A75, 05E10, 20C15, 20F55, 51F15
url https://arxiv.org/abs/2401.08215