Extremum Sum-Connectivity Index of Trees and Unicyclic Graphs

Abstract

The sum-connectivity index of a graph G is defined as the sum of weights 1/root d(w) +d(z ) over all edges wz of G, where d(w) and d(z) are the degrees of the vertices w and z in G, respectively. In this paper, we provide a simpler method to the extremal trees and unicyclic graph of the sum-connectivity index.