On the semigroup of order-decreasing partial isometries of a finite chain

R. Kehinde, S. O. Makanjuola, A. Umar

Let ${\mathcal{I}}_n$ be the symmetric inverse semigroup on $X_n=\{1,2,...,n\}$ and let ${\mathcal{DDP}}_n$ and ${\mathcal{O}\mathcal{DDP}}_n$ be its subsemigroups of order-decreasing partial isometrie…