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

Fuente: arXiv
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Main Authors: Kessar, Radha, Malle, Gunter, Semeraro, Jason
Format: Preprint
Published: 2025
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author Kessar, Radha
Malle, Gunter
Semeraro, Jason
author_facet Kessar, Radha
Malle, Gunter
Semeraro, Jason
contents Let ${\mathbb{G}}$ be a simply connected ${\mathbb{Z}}_\ell$-spets, let $q$ be a prime power, prime to $\ell$ and let $S$ 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 ${\mathbb{G}}(q)$ on the elements of $S$. Using this, we explicitly list the unipotent character values of the ${\mathbb{Z}}_2$-spets $G_{24}(q)$ related to the Benson-Solomon fusion system Sol$(q)$. Secondly, when $\ell > 2$ is a very good prime for ${\mathbb{G}}$, the Weyl group $W$ of ${\mathbb{G}}$ has order coprime with $\ell$, and $q\equiv1\pmod\ell$ we introduce a formula for the values of characters in the principal block of ${\mathbb{G}}(q)$ 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.
format Preprint
id arxiv_https___arxiv_org_abs_2507_08502
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Partial character tables for $\mathbb{Z}_\ell$-spetses
Kessar, Radha
Malle, Gunter
Semeraro, Jason
Representation Theory
Group Theory
20C08, 20C20, 20F55, 16G30, 20D20, 55R35
Let ${\mathbb{G}}$ be a simply connected ${\mathbb{Z}}_\ell$-spets, let $q$ be a prime power, prime to $\ell$ and let $S$ 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 ${\mathbb{G}}(q)$ on the elements of $S$. Using this, we explicitly list the unipotent character values of the ${\mathbb{Z}}_2$-spets $G_{24}(q)$ related to the Benson-Solomon fusion system Sol$(q)$. Secondly, when $\ell > 2$ is a very good prime for ${\mathbb{G}}$, the Weyl group $W$ of ${\mathbb{G}}$ has order coprime with $\ell$, and $q\equiv1\pmod\ell$ we introduce a formula for the values of characters in the principal block of ${\mathbb{G}}(q)$ 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.
title Partial character tables for $\mathbb{Z}_\ell$-spetses
topic Representation Theory
Group Theory
20C08, 20C20, 20F55, 16G30, 20D20, 55R35
url https://arxiv.org/abs/2507.08502