Sigma index and forgotten index of the subdivision and r-subdivision graphs

Abstract

Topological graph indices are defined and used by mathematicians and chemists to obtain some chemical properties of a molecule under consideration by calculating the related topological index obtained from the graph modelling the molecule. This saves one from a lot of laboratory work and its labor and cost. In this paper, we concentrate on two of these topological graph indices, namely the sigma index and the forgotten index of a graph. We calculate these two indices for the subdivision and r-subdivision graphs and give examples for some well-known graph classes.