Non-solvable graphs of groups

Abstract

Let $G$ be a group and $Sol(G)=\{x\in G:⟨x,y⟩\text{ is solvable for all }y\in G\}$. We associate a graph ${\mathcal{N}\mathcal{S}}_G$ (called the non-solvable graph of $G$) with $G$ whose vertex set is $G\setminus Sol(G)$ and two distinct vertices are adjacent if they generate a non-solvable subgroup. In this paper we study many properties of ${\mathcal{N}\mathcal{S}}_G$. In particular, we obtain results on vertex degree, cardinality of vertex degree set, graph realization, domination number, vertex connectivity, independence number and clique number of ${\mathcal{N}\mathcal{S}}_G$. We also consider two groups $G$ and $H$ having isomorphic non-solvable graphs and derive some properties of $G$ and $H$. Finally, we conclude this paper by showing that ${\mathcal{N}\mathcal{S}}_G$ is neither planar, toroidal, double-toroidal, triple-toroidal nor projective.

17 pages