{ "id": "1708.05646", "version": "v1", "published": "2017-08-18T15:20:26.000Z", "updated": "2017-08-18T15:20:26.000Z", "title": "On the character degrees of a Sylow $p$-subgroup of a finite Chevalley group $G(p^f)$ over a bad prime", "authors": [ "Tung Le", "Kay Magaard", "Alessandro Paolini" ], "comment": "14 pages", "categories": [ "math.RT", "math.GR" ], "abstract": "Let $q$ be a power of a prime $p$ and let $U(q)$ be a Sylow $p$-subgroup of a finite Chevalley group $G(q)$ defined over the field with $q$ elements. We first give a parametrization of the set $\\text{Irr}(U(q))$ of irreducible characters of $U(q)$ when $G(q)$ is of type $\\mathrm{G}_2$. This is uniform for primes $p \\ge 5$, while the bad primes $p=2$ and $p=3$ have to be considered separately. We then use this result and the contribution of several authors to show a general result, namely that if $G(q)$ is any finite Chevalley group with $p$ a bad prime, then there exists a character $\\chi \\in \\text{Irr}(U(q))$ such that $\\chi(1)=q^n/p$ for some $n \\in \\mathbb{Z}_{\\ge_0}$. In particular, for each $G(q)$ and every bad prime $p$, we construct a family of characters of such degree as inflation followed by an induction of linear characters of an abelian subquotient $V(q)$ of $U(q)$.", "revisions": [ { "version": "v1", "updated": "2017-08-18T15:20:26.000Z" } ], "analyses": { "subjects": [ "20C33" ], "keywords": [ "finite chevalley group", "bad prime", "character degrees", "general result", "linear characters" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable" } } }