How does the restriction of representations change under translations? A story for the general linear groups and the unitary groups

Fuente: arXiv
Enregistré dans:
Détails bibliographiques
Auteurs principaux: Kobayashi, Toshiyuki, Speh, Birgit
Format: Preprint
Publié: 2025
Sujets:
Accès en ligne:
Tags: Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
_version_ 1866918204642689024
author Kobayashi, Toshiyuki
Speh, Birgit
author_facet Kobayashi, Toshiyuki
Speh, Birgit
contents We present a new approach to symmetry breaking for pairs of real forms of $(GL(n, \mathbb{C}), GL(n-1, \mathbb{C}))$. Translation functors are powerful tools for studying families of representations of a single reductive group $G$. However, when applied to a pair of groups $G \supset G'$, they can significantly alter the nature of symmetry breaking between the representations of $G$ and $G'$, even within the same Weyl chamber of the direct product group $G \times G'$. We introduce the concept of "fences for the interleaving pattern", which provides a refinement of the usual notion of walls of Weyl chambers. We then establish a theorem stating that the multiplicity remains constant unless these "fences" are crossed, together with a new general vanishing theorem for symmetry breaking. These general results are illustrated with examples involving both tempered and non-tempered representations. In addition, we present a new non-vanishing theorem for period integrals for pairs of reductive symmetric spaces, which is further strengthened by this approach.
format Preprint
id arxiv_https___arxiv_org_abs_2502_08479
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle How does the restriction of representations change under translations? A story for the general linear groups and the unitary groups
Kobayashi, Toshiyuki
Speh, Birgit
Representation Theory
We present a new approach to symmetry breaking for pairs of real forms of $(GL(n, \mathbb{C}), GL(n-1, \mathbb{C}))$. Translation functors are powerful tools for studying families of representations of a single reductive group $G$. However, when applied to a pair of groups $G \supset G'$, they can significantly alter the nature of symmetry breaking between the representations of $G$ and $G'$, even within the same Weyl chamber of the direct product group $G \times G'$. We introduce the concept of "fences for the interleaving pattern", which provides a refinement of the usual notion of walls of Weyl chambers. We then establish a theorem stating that the multiplicity remains constant unless these "fences" are crossed, together with a new general vanishing theorem for symmetry breaking. These general results are illustrated with examples involving both tempered and non-tempered representations. In addition, we present a new non-vanishing theorem for period integrals for pairs of reductive symmetric spaces, which is further strengthened by this approach.
title How does the restriction of representations change under translations? A story for the general linear groups and the unitary groups
topic Representation Theory
url https://arxiv.org/abs/2502.08479