On the monoid of partial isometries of a wheel graph

In this paper, we consider the monoid $DPW_n$ of all partial isometries of a wheel graph $W_n$ with $n+1$ vertices. Our main objective is to determine the rank of $DPW_n$. In the process, we also compute the ranks of three notable subsemigroups of $DPW_n$. We also describe Green's relations of $DPW_n$ and of its three considered subsemigroups.