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 $n_u$ and $n_v$ over all edges $uv$ of $G$,  where $n_u$ and $n_v$ 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 pendant vertices using graph transformations that decrease or increase the Mostar index.