Extremal Sombor Index of Graphs with Cut Edges and Clique Number

Abstract

The Sombor index is defined as SO(G)=∑uv∈E(G)d2(u)+d2(v), where d(u) and d(v) represent the number of edges in the graph G connected to the vertices u and v, respectively. In this paper, we characterize the largest and second largest Sombor indexes with a given number of cut edges. Moreover, we determine the upper and lower sharp bounds of the Sombor index with a given number of clique numbers, and we characterize the extremal graphs.