Classifying integral graphs is a hard problem that initiated by Harary and Schwenk in 1974. In this paper, with the help of character table, we treat corresponding for Cayley over semi-dihedral group SD8n = ?a,b | a4n b2 1; bab a2n-1?, n ? 2. We present several necessary sufficient conditions integrality SD8n, also obtain some simple terms Boolean algebra hai. particular, give groups SD2n (n?4)...

In this paper we consider the critical group of finite connected graphs which admit harmonic actions by the dihedral group Dn. In particular, we show that if the orbits of the Dn-action all have either n or 2n points then the critical group of such a graph can be decomposed in terms of the critical groups of the quotients of the graph by certain subgroups of the automorphism group. This is anal...

The holomorph of a group G is NormB(λ(G)), the normalizer of the left regular representation λ(G) in its group of permutations B = Perm(G). The multiple holomorph of G is the normalizer of the holomorph in B. The multiple holomorph and its quotient by the holomorph encodes a great deal of information about the holomorph itself and about the group λ(G) and its conjugates within the holomorph. We...