چكيده فارسي :
Let G1,G2, …, Gk be simple graphs and xi be an arbitrary vertex of Gi, i = 1, 2, …, k.
For any simple graph H with vertex set {x1, x2, …, xk}, the graph G obtained by the
union G1, G2, …, Gk and H is denoted by K = H(G1,G2, …, Gk). In this paper we
calculate characteristic polynomial of adjacency matrix of this graph in terms of the
characteristic polynomial of the graphs Gi and H. We also consider some special
cases for the graphs Gi and H, and calculate spectra of K.
