Signs of self-dual depth-zero supercuspidal representations

TL;DR

This paper investigates conditions under which self-dual supercuspidal representations exist for certain p-adic groups and characterizes their Frobenius-Schur indicators in terms of central elements.

Contribution

It establishes the existence of self-dual supercuspidal representations under specific Weyl group conditions and relates their Frobenius-Schur indicators to central elements for unramified groups.

Findings

Self-dual supercuspidal representations exist if -1 is in the F-points of the absolute Weyl group.

The Frobenius-Schur indicator is determined by the action of a central element of order two.

Explicit relation between the indicator and the central element's sign action.

Abstract

Let $G$ be a quasi-split tamely ramified connected reductive group defined over a $p$-adic field $F$. We show that if $-1$ is in the $F$-points of the absolute Weyl group of $G$, then self-dual supercuspidal representations of $G(F)$ exist. Now assume further that $G$ is unramified and that the center of $G$ is connected. Let $\pi$ be a generic self-dual depth-zero regular supercuspidal representation of $G(F)$. We show that the Frobenius-Schur indicator of $\pi$ is given by the sign by which a certain distinguished element of the center of $G(F)$ of order two acts on $\pi$.