Перегляд Відділення математики за автором "Umar, A."

Результати 1-3 з 3

On certain semigroups of contraction mappings of a finite chain

Umar, A.; Zubairu, M.M. (Algebra and Discrete Mathematics, 2021)

Let [n] = {1, 2, . . . , n} be a finite chain and let Pn (resp. , Tn) be the semigroup of partial transformations on [n] (resp. , full transformations on [n]). Let CPn = {α ∈ Pn : (for all x, y ∈ Dom α) |xα−yα| ≤ |x−y|} ...
Some combinatorial problems in the theory of partial transformation semigroups

Umar, A. (Algebra and Discrete Mathematics, 2014)

Let Xn = {1,2,…,n}. On a partial transformation α : Dom α ⊆ Xn → Im α ⊆ Xn of Xn the following parameters are defined: the breadth or width of α is ∣ Dom α ∣, the collapse of α is c(α) = ∣ ∪t∈Imα{tα⁻¹ :∣ tα⁻¹ ∣≥ 2} ∣, fix ...
Some combinatorial problems in the theory of symmetric inverse semigroups

Umar, A. (Algebra and Discrete Mathematics, 2010)

Let Xn={1,2,⋯,n} and let α:Domα⊆Xn→Imα⊆Xn be a (partial) transformation on Xn. On a partial one-one mapping of Xn the following parameters are defined: the height of α is h(α)=|Imα|, the right [left] waist of α is ...

Результати 1-3 з 3

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