On the energy and Estrada index of Cayley graphs.

The concept of energy of a graph was first defined in 1978 by Gutman as the sum of the absolute values of the eigenvalues of its adjacency matrix. Let λ1, λ2, ..., λn be eigenvalues of graph Γ, then the Estrada index of Γ is defined as . The aim of this paper is to estimate the energy and Estrada index of Cayley graphs (G, S) where G ≅ D2n, U6n and S is a normal symmetric generating subset of G. [ABSTRACT FROM AUTHOR]