Abstract
Let G be a molecular graph with n vertices, m edges and G(L) be a line graph. Both G and L can be represented by their adjacency matrices A and E, respectively. The eigenvalues of G and L are denoted by, and
respectively. The Estrada index A and L are defined as
and
In this article, we present some new lower and upper bounds for the Estrada index molecular and line graphs of phenylenes.
Acknowledgment
The authors would like to thanks the two anonymous reviewers for their very constructive comments that helped us to enhance the quality of this manuscript.
Disclosure statement
There are no conflicts of interest.