New lower bounds for the Geometric-Arithmetic index

Abstract

The concept of geometric-arithmetic index was introduced in the chemical graph theory recently, but it has shown to be useful. The aim of this paper is to obtain new inequalities involving the geometric-arithmetic index $G{A}_1$ and characterize graphs extremal with respect to them. Our main results provide lower bounds $G{A}_1(G)$ involving just the minimum and the maximum degree of the graph $G$.

12 pages