Let A (G) be the adjacency matrix of a graph G with lambda(1)(G), lambda(2)(G), ..., lambda(n)(G) its eigenvalues in non-increasing order. Call the number S-k(G) := Sigma(n)(i=1) lambda(k)(i)(G)(k=0,1,...,n-1) the kth spectral moment of G. Let S (G) = (S-0(G), S-1(G),...,Sn-1(G)) be the sequence of spectral moments of G. For two graphs G(1) and G(2), we have G(1)
