English

Partial character tables for $\mathbb{Z}_\ell$-spetses

Representation Theory 2025-07-14 v1 Group Theory

Abstract

Let G{\mathbb{G}} be a simply connected Z{\mathbb{Z}}_\ell-spets, let qq be a prime power, prime to \ell and let SS be the underlying Sylow \ell-subgroup. Firstly, motivated by known formulae for values of Deligne-Lusztig characters of finite reductive groups, we propose a formula for the values of the unipotent characters of G(q){\mathbb{G}}(q) on the elements of SS. Using this, we explicitly list the unipotent character values of the Z2{\mathbb{Z}}_2-spets G24(q)G_{24}(q) related to the Benson-Solomon fusion system Sol(q)(q). Secondly, when >2\ell > 2 is a very good prime for G{\mathbb{G}}, the Weyl group WW of G{\mathbb{G}} has order coprime with \ell, and q1(mod)q\equiv1\pmod\ell we introduce a formula for the values of characters in the principal block of G(q){\mathbb{G}}(q) which extends the Curtis-Schewe type formulae for groups of Lie type, and which we show to satisfy a version of block orthogonality. In both cases we formulate and provide evidence for several conjectures concerning the proposed values.

Keywords

Cite

@article{arxiv.2507.08502,
  title  = {Partial character tables for $\mathbb{Z}_\ell$-spetses},
  author = {Radha Kessar and Gunter Malle and Jason Semeraro},
  journal= {arXiv preprint arXiv:2507.08502},
  year   = {2025}
}
R2 v1 2026-07-01T03:56:25.957Z