TEMO theorem for Sombor index

TEMO = topological effect on molecular orbitals was discovered by Polansky and Zander in 1982, in connection with the eigenvalues of molecular graphs. Eventually, analogous regularities were established for a variety of other topological indices. We now show that a TEMO-type regularity also holds for the Sombor index ( S O ): For the graphs S and T , constructed by connecting a pair of vertex-disjoint graphs by two edges, S O ( S ) < S O ( T ) holds. Analogous relations are verified for several other degree-based graph invariants.