A Classification Of Tetravalent Cayley Graphs Of Quasi-dihedral Group Of Order 16ρ

Let G be a finite group and S a subset of G such that 1(?)S. A Cayley graph X=Cay(G,S) of a group G is said to be normal if R(G), the group of right multiplications is normal in Aut(X). In this paper, by investigating their normality, we classify 4-valent Cayley graphs of quasi-dihedral groups of order 16p, G=<a,b|a8p=b2=1,ab=a4p+1). where p is an odd prime. In addition we obtain an infinite families of nonnormal Cayley graphs of quasi-dihedral groups.