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Simple exceptional groups of Lie type are determined by their character degrees

Group Theory 2011-02-23 v1 Representation Theory

Abstract

Let GG be a finite group. Denote by Irr(G)\textrm{Irr}(G) the set of all irreducible complex characters of G.G. Let cd(G)={χ(1)    χIrr(G)}\textrm{cd}(G)=\{\chi(1)\;|\;\chi\in \textrm{Irr}(G)\} be the set of all irreducible complex character degrees of GG forgetting multiplicities, and let X1(G)\textrm{X}_1(G) be the set of all irreducible complex character degrees of GG counting multiplicities. Let HH be any non-abelian simple exceptional group of Lie type. In this paper, we will show that if SS is a non-abelian simple group and cd(S)cd(H)\textrm{cd}(S)\subseteq \textrm{cd}(H) then SS must be isomorphic to H.H. As a consequence, we show that if GG is a finite group with X1(G)X1(H)\textrm{X}_1(G)\subseteq \textrm{X}_1(H) then GG is isomorphic to H.H. In particular, this implies that the simple exceptional groups of Lie type are uniquely determined by the structure of their complex group algebras.

Keywords

Cite

@article{arxiv.1102.4427,
  title  = {Simple exceptional groups of Lie type are determined by their character degrees},
  author = {Hung P. Tong-Viet},
  journal= {arXiv preprint arXiv:1102.4427},
  year   = {2011}
}

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18 pages