Equienergetic Graphs

H. S. Ramane1, H. B. Walikar2, I. Gutman3
1Department of Mathematics Gogte Institute of Technology Udyambag, Belgaum – 590008, India.
2Department of Mathematics Karnatak University Dharwad – 580003, India.
3Faculty of Science University of Kragujevac P. O. Box 60, 34000 Kragujevac, Serbia.

Abstract

The energy \(E(G)\) of a graph \(G\) is the sum of the absolute values of the eigenvalues of \(G\). Two graphs \(G_1\) and \(G_2\) are said to be equienergetic if \(E(G_1) = E(G_2)\). In this paper, we outline various classes of equienergetic graphs. These results enable the construction of pairs of noncospectral equienergetic graphs of the same order and of the same size.

Keywords: Energy of a graph, equienergetic graphs, line graphs, graph product. 2000 Mathematics Subject Classification: 05C