Automorphism group of quasi-abelian semi-Cayley graphs

Abstract

Let G be a group and R,L,S be subsets of G such that $R=R^{-1}$, $L=L^{-1}$ and $1\notin R\cup L$. The undirected graph $\SC(G;R,L,S)$ with vertex set union of $G_1=\{g_1\mid g\in G\}$ and $G_2=\{g_2\mid g\in G\}$, and edge set the union of $\{\{g_1,(gr)_1\}\mid g\in G, r\in R\}$, $\{\{g_2,(gl)_2\}\mid g\in G,l\in L\}$ and $\{\{g_1,(gs)_2\}\mid g\in G,s\in S\}$ is called semi-Cayley graph over G. We say that $\SC(G;R,L,S)$ is quasi-abelian if R,L and S are a union of conjugacy classes of G. In this paper, we study the automorphism group of quasi-abelian semi-Cayley graphs.