The sign of linear periods

Fuente: arXiv
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Autori principali: Anandavardhanan, U. K., Lu, Hengfei, Matringe, Nadir, Sécherre, Vincent, Yang, Chang
Natura: Preprint
Pubblicazione: 2024
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author Anandavardhanan, U. K.
Lu, Hengfei
Matringe, Nadir
Sécherre, Vincent
Yang, Chang
author_facet Anandavardhanan, U. K.
Lu, Hengfei
Matringe, Nadir
Sécherre, Vincent
Yang, Chang
contents Let $G$ be a group with subgroup $H$, and let $(π,V)$ be a complex representation of $G$. The natural action of the normalizer $N$ of $H$ in $G$ on the space $\mathrm{Hom}_H(π,\mathbb{C})$ of $H$-invariant linear forms on $V$, provides a representation $χ_π$ of $N$ trivial on $H$, which is a character when $\mathrm{Hom}_H(π,\mathbb{C})$ is one dimensional. If moreover $G$ is a reductive group over a local field, and $π$ is smooth irreducible, it is an interesting problem to express $χ_π$ in terms of the possibly conjectural Langlands parameter $ϕ_π$ of $π$. In this paper we consider the following situation: $G=\mathrm{GL}_m(D)$ for $D$ a central division algebra of dimension $d^2$ over a local field $F$ of characteristic zero, $H$ is the centralizer of a non central element $δ\in G$ such that $δ^2$ is in the center of $G$, and $π$ has generic Jacquet-Langlands transfer to $\mathrm{GL}_{md}(F)$. In this setting the space $\mathrm{Hom}_H(π,\mathbb{C})$ is at most one dimensional. When $\mathrm{Hom}_H(π,\mathbb{C})\simeq \mathbb{C}$ and $H\neq N$, we prove that the value of the $χ_π$ on the non trivial class of $\frac{N}{H}$ is $(-1)^mε(ϕ_π)$ where $ε(ϕ_π)$ is the root number of $ϕ_π$. Along the way we extend many useful multiplicity one results for linear and Shalika models to the case of non split $G$. When $F$ is $p$-adic we also classify standard modules with linear periods and Shalika models, which are new results even when $D=F$.
format Preprint
id arxiv_https___arxiv_org_abs_2402_12106
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The sign of linear periods
Anandavardhanan, U. K.
Lu, Hengfei
Matringe, Nadir
Sécherre, Vincent
Yang, Chang
Representation Theory
22E50, 11F70
Let $G$ be a group with subgroup $H$, and let $(π,V)$ be a complex representation of $G$. The natural action of the normalizer $N$ of $H$ in $G$ on the space $\mathrm{Hom}_H(π,\mathbb{C})$ of $H$-invariant linear forms on $V$, provides a representation $χ_π$ of $N$ trivial on $H$, which is a character when $\mathrm{Hom}_H(π,\mathbb{C})$ is one dimensional. If moreover $G$ is a reductive group over a local field, and $π$ is smooth irreducible, it is an interesting problem to express $χ_π$ in terms of the possibly conjectural Langlands parameter $ϕ_π$ of $π$. In this paper we consider the following situation: $G=\mathrm{GL}_m(D)$ for $D$ a central division algebra of dimension $d^2$ over a local field $F$ of characteristic zero, $H$ is the centralizer of a non central element $δ\in G$ such that $δ^2$ is in the center of $G$, and $π$ has generic Jacquet-Langlands transfer to $\mathrm{GL}_{md}(F)$. In this setting the space $\mathrm{Hom}_H(π,\mathbb{C})$ is at most one dimensional. When $\mathrm{Hom}_H(π,\mathbb{C})\simeq \mathbb{C}$ and $H\neq N$, we prove that the value of the $χ_π$ on the non trivial class of $\frac{N}{H}$ is $(-1)^mε(ϕ_π)$ where $ε(ϕ_π)$ is the root number of $ϕ_π$. Along the way we extend many useful multiplicity one results for linear and Shalika models to the case of non split $G$. When $F$ is $p$-adic we also classify standard modules with linear periods and Shalika models, which are new results even when $D=F$.
title The sign of linear periods
topic Representation Theory
22E50, 11F70
url https://arxiv.org/abs/2402.12106