Hitting-Time Index of Trees: Bounds, Relationships, and Exact Formulas

Abstract

The hitting-time index is a recently introduced topological molecular descriptor based on graph distance. Its lower and upper bounds for trees, in terms of other graph invariants, are derived. In particular, the hitting-time index is related to the eccentric connectivity index, total eccentricity, eccentric distance sum, and degree distance index. Additionally, a closed formula for the hitting-time index of double brooms is obtained.