English

Rational conjugacy classes and rational characters for some finite simple groups

Group Theory 2025-03-27 v1 Representation Theory

Abstract

If GG is a finite group, an irreducible complex-valued character χ\chi is called rational if χ(g)\chi(g) is rational for all gGg\in G. Also, a conjugacy class xGx^G is called rational, if for all irreducible complex-valued character χ\chi, the value χ(xG)\chi(x^G) is rational. We prove that for qq, a power of prime, the group PSL2(q)\mathrm{PSL}_2(q) has same number of rational characters and rational conjugacy classes. Furthermore, we verify that this equality holds for all finite simple groups whose character tables appear in the ATLAS of Finite Groups\textit{ATLAS of Finite Groups}, except for the Tits group.

Keywords

Cite

@article{arxiv.2503.20452,
  title  = {Rational conjugacy classes and rational characters for some finite simple groups},
  author = {Dilpreet Kaur and Saikat Panja},
  journal= {arXiv preprint arXiv:2503.20452},
  year   = {2025}
}

Comments

Preliminary version; 14 pages; 1 table; comments welcome

R2 v1 2026-06-28T22:35:01.810Z