A graph operation and its applications in orderenergetic graphs
The energy E(G)of a graph G is defined as the absolute sum of the eigenvalues of its adjacency matrix.A graph G of order n is called an orderenergetic graph if E(G)=n.In this paper,we introduce a new graph operation by combining the graph and the matrix calculation,especially the Kronecker product of matrices.Furthermore,we obtain the adjacency spectrum of the result graph.And we construct infinite families of new orderenergetic graphs from a non-orderenergetic graph.Also,we generate three new classes of orderenergetic graphs from any orderenergetic graph.