W. Sommanee

collaborators

3 papers

math.GR2024

Regularity of the semigroup of transformations preserving a length

Worachead Sommanee

Let $X_{n} = {1, 2, \dots, n}$ be a finite set $(n \geq 2)$ and $T_{n}$ the full transformation semigroup on $X_{n}$ . For a positive integer $l \leq n - 1$ , we define $$T_n(l) = \{α\in T_n \c…

math.GR2017

Sandwich semigroups in locally small categories II: Transformations

Igor Dolinka, Ivana Ðurđev, James East +4

Fix sets $X$ and $Y$ , and write $P T_{X Y}$ for the set of all partial functions $X \to Y$ . Fix a partial function $a : Y \to X$ , and define the operation $⋆_{a}$ on $\mathca…

math.GR2017

Sandwich semigroups in locally small categories I: Foundations

Igor Dolinka, Ivana Đurđev, James East +4

Fix (not necessarily distinct) objects $i$ and $j$ of a locally small category $S$ , and write $S_{ij}$ for the set of all morphisms $i \to j$ . Fix a morphism $a \in S_{j i}$ , and defi…