On the Hitting Time Index of Graphs

The hitting time index of a simple connected undirected graph G is a recently defined topological descriptor, HT( G ) , which is computed using the expected hitting times of the random walk on G . In this article, we find a new upper bound for HT( G ) , given in terms of the Kirchhoff index, and a new degree-weighted Kirchhoff index. Then we look at HT( G ) when G is edge transitive, both in the regular and non-regular cases. We find closed-form formulas for some families of Cayley graphs, the complete bipartite graphs K m,n , and some subdivision graphs.