Asian-European Journal of Mathematics, 2026 (ESCI, Scopus)
Let PMDn be the semigroup consisting of all monotone and order-decreasing partial transformations, and let PCn be the subsemigroup of PMDn consisting of all order-preserving and order-decreasing partial transformations on the finite chain (Formula presented). In this paper, we determine the maximal subsemigroups of PMD(n,r), and moreover, we show that the smallest number of elements of PMD(n,r) which, together with PC(n,r), generate PMD(n,r) is n − 2 for every 2 ≤ r ≤ n.