摘要
Let G be a graph and denote by Q(G)=D(G)+A(G),L(G)=D(G)-A(G) the sum and the difference between the diagonal matrix of vertex degrees and the adjacency matrix of G, respectively.In this paper,some properties of the matrix Q(G) are studied.At the same time,a necessary and sufficient condition for the equality of the spectrum of Q(G) and L(G) is given.
Let G be a graph and denote by Q(G)=D(G)+A(G),L(G)=D(G)-A(G) the sum and the difference between the diagonal matrix of vertex degrees and the adjacency matrix of G, respectively.In this paper,some properties of the matrix Q(G) are studied.At the same time,a necessary and sufficient condition for the equality of the spectrum of Q(G) and L(G) is given.
