Harary spectrum of generalized composition of graphs and Harary equienergetic graphs

Abstract

The Harary spectrum of a connected graph $G$ is the collection of the eigenvalues of its Harary matrix. The Harary energy of a graph $G$ is the sum of absolute values of its Harary eigenvalues. Harary equitable partition is defined and is used to obtain Harary spectrum of generalized composition of graphs. Harary equienergetic graphs have been constructed with the help of generalized composition through Harary equitable partition.