English

The binary actions of simple groups of Lie type of characteristic 2

Group Theory 2025-05-28 v1

Abstract

Let C\mathcal{C} be a conjugacy class of involutions in a group GG. We study the graph Γ(C)\Gamma(\mathcal{C}) whose vertices are elements of C\mathcal{C} with g,hCg,h\in\mathcal{C} connected by an edge if and only if ghCgh\in\mathcal{C}. For tCt\in \mathcal{C}, we define the component group of tt to be the subgroup of GG generated by all vertices in Γ(C)\Gamma(\mathcal{C}) that lie in the connected component of the graph that contains tt. We classify the component groups of all involutions in simple groups of Lie type over a field of characteristic 22. We use this classification to partially classify the transitive binary actions of the simple groups of Lie type over a field of characteristic 22 for which a point stabilizer has even order. The classification is complete unless the simple group in question is a symplectic or unitary group.

Keywords

Cite

@article{arxiv.2402.08357,
  title  = {The binary actions of simple groups of Lie type of characteristic 2},
  author = {Nick Gill and Pierre Guillot and Martin W. Liebeck},
  journal= {arXiv preprint arXiv:2402.08357},
  year   = {2025}
}