Character values and Hochschild homology
Abstract
We present a conjecture (and a proof for G=SL(2)) generalizing a result of J. Arthur which expresses a character value of a cuspidal representation of a -adic group as a weighted orbital integral of its matrix coefficient. It also generalizes a conjecture by the second author proved by Schneider-Stuhler and (independently) the first author. The latter statement expresses an elliptic character value as an orbital integral of a pseudo-matrix coefficient defined via the Chern character map taking value in zeroth Hochschild homology of the Hecke algebra. The present conjecture generalizes the construction of pseudo-matrix coefficient using compactly supported Hochschild homology, as well as a modification of the category of smooth representations, the so called compactified category of smooth -modules. This newly defined "compactified pseudo-matrix coefficient" lies in a certain space on which the weighted orbital integral is a conjugation invariant linear functional, our conjecture states that evaluating a weighted orbital integral on the compactified pseudo-matrix coefficient one recovers the corresponding character value of the representation. We also discuss general properties of that space, building on works of Waldspurger and Beuzart-Plessis.
Cite
@article{arxiv.1803.09442,
title = {Character values and Hochschild homology},
author = {Roman Bezrukavnikov and David Kazhdan},
journal= {arXiv preprint arXiv:1803.09442},
year = {2018}
}
Comments
A funding acknowledgment is the only change from the previous version. 26pp