University of KashanIranian Journal of Mathematical Chemistry2228-648915120240301Improved Estimates of Sombor Index1511423810.22052/ijmc.2023.253825.1782ENIvanGutmanFaculty of Science, University of Kragujevac, Kragujevac, Serbia0000-0001-9681-1550Journal Article20231105The Sombor index $(SO)$ is a recently invented vertex-degree-based molecular structure-descriptor. Let $M_1$ be the first Zagreb index. The fact that $SO$ is bounded from below by $M_{1}/\sqrt{2}$ and from above by $M_{1}$ is well-known and easy to prove. In this paper, we improve these bounds.https://ijmc.kashanu.ac.ir/article_114238_b488c8c6facd0966648ca8841f4d2081.pdf