Lifting semisimple characters of $p$-adic types from fixed-point subgroups

Fuente: arXiv
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Autores principales: Bourgeois, Adèle, Nevins, Monica
Formato: Preprint
Publicado: 2026
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author Bourgeois, Adèle
Nevins, Monica
author_facet Bourgeois, Adèle
Nevins, Monica
contents Given a $p$-adic group $G=\mathbf{G}(F)$ and a finite group $Γ\subset\mathrm{Aut}_F(\mathbf{G})$ such that the fixed-point subgroup $\mathbf{G}^Γ$ is reductive, we show that every semisimple character (in the sense of Bushnell and Kutzko) of a type for $G^Γ= \mathbf{G}^Γ(F)$ arises as the restriction of a semisimple character of a type for $G$. We achieve this by explicitly lifting the truncated Kim--Yu datum (or character-datum) that parametrizes the semisimple character for $G^Γ$ to a character-datum that parametrizes a semisimple character for $G$. Our proof, which is of independent interest, uses state-of-the-art techniques and, as a special case, defines a lift of a Howe factorization of a character of a maximal torus of $G^Γ$.
format Preprint
id arxiv_https___arxiv_org_abs_2602_13018
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Lifting semisimple characters of $p$-adic types from fixed-point subgroups
Bourgeois, Adèle
Nevins, Monica
Representation Theory
22E50
Given a $p$-adic group $G=\mathbf{G}(F)$ and a finite group $Γ\subset\mathrm{Aut}_F(\mathbf{G})$ such that the fixed-point subgroup $\mathbf{G}^Γ$ is reductive, we show that every semisimple character (in the sense of Bushnell and Kutzko) of a type for $G^Γ= \mathbf{G}^Γ(F)$ arises as the restriction of a semisimple character of a type for $G$. We achieve this by explicitly lifting the truncated Kim--Yu datum (or character-datum) that parametrizes the semisimple character for $G^Γ$ to a character-datum that parametrizes a semisimple character for $G$. Our proof, which is of independent interest, uses state-of-the-art techniques and, as a special case, defines a lift of a Howe factorization of a character of a maximal torus of $G^Γ$.
title Lifting semisimple characters of $p$-adic types from fixed-point subgroups
topic Representation Theory
22E50
url https://arxiv.org/abs/2602.13018