A. Umar

activity

20102022

most citedA countable family of finitely presented infinite congruence-free monoids

2 citations · 4 across the 10 of their papers we have counts for

collaborators

Showing 2022Show all

3 papers · 1 filter

math.GR2022

On the combinatorial and rank properties of certain subsemigroups of full contractions of a finite chain

Muhammad Mansur Zubairu, Abdullahi Umar, Muhammad Jada Aliyu

Let $[n] = {1, 2, \dots, n}$ be a finite chain and let $C T_{n}$ be the semigroup of full contractions on $[n]$ . Denote $O R C T_{n}$ and $O C T_{n}$ to be th…

math.GR2022★ 1 cited

On certain Semigroup of Order-decreasing Full Contraction Mappings of a Finite Chain

M. M. Zubairu, A. Umar, J. A. Aliyu

Let $C T_{n}$ be the semigroup of full contraction mappings on $[n] = {1, 2, \dots, n}$ , and let $O C T_{n}$ and $O D C T_{n}$ be the subsemigroups consisting of al…

math.CO2022

Combinatorial results for order-preserving partial injective contraction mappings

Bayo Musa Ahmed, Nadia Aldhamri, Fatma Al-Kharousi +2

Let $I_{n}$ be the symmetric inverse semigroup on $X_{n} = {1, 2, \dots, n}$ . Let $O C I_{n}$ be the subsemigroup of $I_{n}$ consisting of all order-preser…