Automorphism Groups of the $PSL_2(q)$ Commuting Involution Graphs

Abstract

Given a finite group $G$ and a conjugacy class of involutions $X$ of $G$, we define the commuting involution graph $\mathcal{C}(G,X)$ to be the graph with vertex set $X$ and $x,y \in X$ adjacent if and only if $x \neq y$ and $xy =yx$. In this paper the automorphism group of the graph $\mathcal{C}(G,X)$ is determined when $G = PSL_2(q)$.