English

Rational rigidity for E_8(p)

Group Theory 2019-02-20 v2 Algebraic Geometry Number Theory Representation Theory

Abstract

We prove the existence of certain rationally rigid triples E8 in good characteristic and thereby show that these groups over the prime field occur as Galois groups over the field of rational numbers. We show that these triples give rise to rigid triples in the algebraic group and prove that they generate an interesting subgroup in characteristic 0. As a byproduct we derive a remarkable symmetry between the character table of a finite reductive group and that of its dual group. We also give a classification of possible overgroups in exceptional groups containing regular unipotent elements.

Keywords

Cite

@article{arxiv.1207.1464,
  title  = {Rational rigidity for E_8(p)},
  author = {Robert Guralnick and Gunter Malle},
  journal= {arXiv preprint arXiv:1207.1464},
  year   = {2019}
}

Comments

The triples considered for F4 in the first paper are shown not to generate F4(p) but rather generate a subgroup contained in a parabolic subgroup over the prime field

R2 v1 2026-06-21T21:31:31.477Z