A. Umar

collaborators

4 papers

math.GR2025

The monoid of monotone and decreasing partial transformations on a finite chain

Muhammad Mansur Zubairu, Abdullahi Umar, Fatma Salim Al-Kharousi

In this article, we consider the monoid of all monotone and order-decreasing partial transformations denoted as $D O RP_{n}$ on an $n$ ordered chain $[n] = {1, \dots, n}$ ,…

math.GR2025

On the small SchrÃ¶der semigroup $SS_{n}^{'}$

Muhammad Mansur Zubairu, Abdullahi Umar, Fatma Salim Al-Kharousi

Let $[n]$ be a finite $n -$ chain ${1, 2, \dots, n}$ , and let $LS_{n}$ be the SchrÃ¶der monoid, consisting of all isotone and order-decreasing partial transformations on…

math.GR2024

On injective partial Catalan monoids

F. S. Al-Kharousi, A. Umar, M. M. Zubairu

Let $[n]$ be a finite chain ${1, 2, \dots, n}$ , and let $I C_{n}$ be the semigroup consisting of all isotone and order-decreasing injective partial transformations on $…

math.GR2024

On the algebraic structure of the SchrÃ¶der monoid

Muhammad Mansur Zubairu, Abdullahi Umar, Fatma Salim Al-Kharousi

Let $[n]$ be a finite chain ${1, 2, \dots, n}$ , and let $LS_{n}$ be the semigroup consisting of all isotone and order-decreasing partial transformations on $[n]$ . More…

The monoid of monotone and decreasing partial transformations on a finite chain

On the small SchrÃ¶der semigroup SSn′​

On injective partial Catalan monoids

On the algebraic structure of the SchrÃ¶der monoid

On the small SchrÃ¶der semigroup $SS_{n}^{'}$