English

Non-solvable groups whose character degree graph has a cut-vertex. II

Group Theory 2022-09-16 v2

Abstract

Let GG be a finite group, and let cd(G){\rm{cd}}(G) denote the set of degrees of the irreducible complex characters of GG. Define then the character degree graph Δ(G)\Delta(G) as the (simple undirected) graph whose vertices are the prime divisors of the numbers in cd(G){\rm{cd}}(G), and two distinct vertices pp, qq are adjacent if and only if pqpq divides some number in cd(G){\rm{cd}}(G). This paper continues the work, started in [7], toward the classification of the finite non-solvable groups whose degree graph possesses a cut-vertex, i.e., a vertex whose removal increases the number of connected components of the graph. While, in [7], groups with no composition factors isomorphic to PSL2(ta){\rm{PSL}}_2(t^a) (for any prime power ta4t^a\geq 4) were treated, here we consider the complementary situation in the case when tt is odd and ta>5t^a> 5. The proof of this classification will be then completed in the third and last paper of this series ([8]), that deals with the case t=2t=2.

Keywords

Cite

@article{arxiv.2208.03519,
  title  = {Non-solvable groups whose character degree graph has a cut-vertex. II},
  author = {Silvio Dolfi and Emanuele Pacifici and Lucia Sanus},
  journal= {arXiv preprint arXiv:2208.03519},
  year   = {2022}
}
R2 v1 2026-06-25T01:32:12.462Z