Extremal problems on the general Sombor index of a graph

Abstract

In this work we obtain new lower and upper optimal bounds of general Sombor indices. Specifically, we get inequalities for these indices relating them with other indices: the first Zagreb index, the forgotten index and the first variable Zagreb index. Finally, we solve some extremal problems for general Sombor indices.

Keywords

• sombor indices
• variable indices
• degree-based topological indices
• inequalities