English

Representations with the same degree

Representation Theory 2026-02-24 v2

Abstract

In this short note we show that every connected reductive simply-connected algebraic group of rank >1>1 over the complex numbers has infinitely many pairs of irreducible representations which are not related by an automorphism of the algebraic group and which have the same degree. This answers a question I was asked by J.~P.~Serre.

Keywords

Cite

@article{arxiv.2601.18786,
  title  = {Representations with the same degree},
  author = {Frank Lübeck},
  journal= {arXiv preprint arXiv:2601.18786},
  year   = {2026}
}

Comments

Corrected notation for G_2 to Bourbaki convention. Added a few remarks in the end