English

Local character expansion for mod-$\ell$ representations

Representation Theory 2025-10-24 v1 Number Theory

Abstract

Let GG be a pp-adic reductive group with pp ``very large.'' For any irreducible admissible representation π\pi of GG over an algebraically closed field CC of characteristic p\not=p, we define a ``local character expansion'' of π\pi with coefficients cO(π)Qc_{\mathcal{O}}(\pi)\in\mathbb{Q}, that does not use the character of π\pi directly but instead use the multiplicities of degenerate Moy-Prasad types. Note that the existence of local character expansion for mod-\ell representations is shown by another paper of the author using a different and quicker method.

Keywords

Cite

@article{arxiv.2510.20510,
  title  = {Local character expansion for mod-$\ell$ representations},
  author = {Cheng-Chiang Tsai},
  journal= {arXiv preprint arXiv:2510.20510},
  year   = {2025}
}

Comments

The result of this paper is mostly superseded by another paper of myself uploaded on the same day. The method presented here may still be of interest

R2 v1 2026-07-01T07:02:03.973Z