English

Representations of reductive groups distinguished by symmetric subgroups

Representation Theory 2017-11-27 v2

Abstract

Let GG be a complex reductive group and H=GθH=G^{\theta} be its fixed point subgroup under a Galois involution θ\theta. We show that any HH-distinguished representation π\pi (i.e dimC(π)H0\mathrm{dim}_{\mathbb{C}}\left(\pi^{*}\right)^{H}\neq0) satisfies: 1) πθπ~\pi^{\theta}\simeq\tilde{\pi}, where π~\tilde{\pi} is the contragredient representation and πθ\pi^{\theta} is the twist of π\pi under θ\theta. 2) dimC(π)HB\G/H\mathrm{dim}_{\mathbb{C}}\left(\pi^{*}\right)^{H}\leq\left|B\backslash G/H\right|, where BB is a Borel subgroup of GG. By proving Statement 1), we give a partial answer to a conjecture by Lapid.

Keywords

Cite

@article{arxiv.1609.00247,
  title  = {Representations of reductive groups distinguished by symmetric subgroups},
  author = {Itay Glazer},
  journal= {arXiv preprint arXiv:1609.00247},
  year   = {2017}
}
R2 v1 2026-06-22T15:37:41.790Z