文摘
Let \(G\) be a finite group and \(S\) be a square-free normal subset of \(G\). The Cayley sum graph \(\mathrm{Cay}^+(G, S)\) of \(G\) with respect to \(S\) is a simple graph whose vertex set is \(G\) and two vertices \(g\) and \(h\) are joined by an edge if and only if \(g h \in S\). In this paper, we obtain necessary and sufficient conditions on \(S\) such that \(\mathrm{Cay}^+(G, S)\) is connected. Also, we prove that if \(G\) is a non-abelian group and \(|S|=3\), then \(\mathrm{Cay}^+(G, S)\) is a connected integral graph if and only if \(G\) is isomorphic to \(S_3\), the symmetric group on \(3\) letters. Keywords Cayley sum graph Integral graph Integral Cayley sum graph