Unitary $L^{p+}$-representations of almost automorphism groups

Let $G$ be a locally compact group with an open subgroup $H$ with the Kunze–Stein property, and let $\pi $ be a unitary representation of $H$. We show that the representation $\widetilde{\pi }$ of $G$ induced from $\pi $ is an $L^{p+}$-representation if and only if $\pi $ is an $L^{p+}$-representati...

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Bibliographic Details
Main Authors: Dabeler, Antje, Mai Elkiær, Emilie, Gerasimova, Maria, de Laat, Tim
Format: Article
Language:English
Published: Académie des sciences 2024-05-01
Series:Comptes Rendus. Mathématique
Online Access:https://comptes-rendus.academie-sciences.fr/mathematique/articles/10.5802/crmath.549/
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Summary:Let $G$ be a locally compact group with an open subgroup $H$ with the Kunze–Stein property, and let $\pi $ be a unitary representation of $H$. We show that the representation $\widetilde{\pi }$ of $G$ induced from $\pi $ is an $L^{p+}$-representation if and only if $\pi $ is an $L^{p+}$-representation. We deduce the following consequence for a large natural class of almost automorphism groups $G$ of trees: For every $p \in (2,\infty )$, the group $G$ has a unitary $L^{p+}$-representation that is not an $L^{q+}$-representation for any $q < p$. This in particular applies to the Neretin groups.
ISSN:1778-3569