Recently, a novel class of degree-based topological molecular descriptors was proposed, the so-called Sombor indices. Within this study, the predictive and discriminative potentials of the Sombor index, the reduced Sombor index, and the average Sombor index were examined. All three topological molecular descriptors showed good predictive potential. The statistical data indicate that the reduced Sombor index preforms with a slightly better predictive potential. An external validation confirmed this finding. It was found that these degree-based indices exert modest discriminative potential, when tested on a large group of isomers.

The ABS (atom-bond sum-connectivity) index is a topological index, that was introduced in 2022 by amalgamating the main ideas of two well-examined indices. Mathematical aspects (especially, extremal results and bounds) of the ABS index have already been studied considerably. The primary goal of this review paper is to collect known bounds and extremal results regarding the ABS index. Several new extremal results, which follow easily from existing general results, are also given. Moreover, a number of open problems and conjectures, arising from the reported results, are proposed.