Inverse Sum Indeg Index (Energy) with Applications to Anticancer Drugs

For a simple graph with vertex set {v1,v2,…,vn} with degree sequence dvi of vertex vi,i=1,2,…,n, the inverse sum indeg matrix (ISI-matrix) AISI(G)=(aij)n×n of G is defined by aij=dvidvjdvi+dvj, if vi is adjacent to vj, and zero, otherwise. The multiset of eigenvalues of AISI(G) is the ISI-spectrum of G and the sum of their absolute values is the ISI-energy of G. In this paper, we modify the two results of (Li, Ye and Broersma, 2022), give the correct characterization of the extremal graphs and thereby obtain better bounds than the already known results. Moreover, we also discuss the QSPR analysis and carry the statistical modelling (linear, logarithmic and quadratic) of the physicochemical properties of anticancer drugs with the ISI-index (energy).