On Mostar index of trees with parameters

Abstract

The Mostar index of a graph G is defined as the sum of absolute values of the differences between nu and nv over all edges uv of G, where nu and nv are respectively, the number of vertices of G lying closer to vertex u than to vertex v and the number of vertices of G lying closer to vertex v than to vertex u. We identify those trees with minimum and/or maximum Mostar index in the families of trees of order n with fixed parameters like the maximum degree, the diameter, number of pendent vertices by using graph transformations that decrease or increase the Mostar index.