• 대한수학회논문집
• /
• 제13권1호
• /
• pp.1-6
• /
• 1998

The paper refers to ordered semigroups in which $x^2 (x \in S)$ are left ideal elements. We mainly show that this $po$-semigroup is left regular if and only if S is a union of left simple subsemigroups of S.

• Korean Journal of Mathematics
• /
• 제10권2호
• /
• pp.117-122
• /
• 2002

In this paper, we give some properties of left(right) semi-regular and $g$-regular $po$-semigroups.

• 호남수학학술지
• /
• 제29권4호
• /
• pp.667-679
• /
• 2007

We study the prime ideal structure of the direct sum of directed system of rings indexed by a commutative semigroup which is nilpotent extension of a group.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• 제12권3호
• /
• pp.215-225
• /
• 2012

We initiate the study of interval-valued fuzzy quasi-ideal of a semigroup. In Section 2, we list some basic definitions in the later sections. In Section 3, we investigate interval-valued fuzzy subsemigroups and in Section 4, we define interval-valued fuzzy quasi-ideals and establish some of their basic properties. In Section 5, we obtain characterizations of regular and intraregular semigroups using the machinery developed in the preceding sections.

• 대한수학회지
• /
• 제46권4호
• /
• pp.775-784
• /
• 2009

In 1932, Lehmer [4] gave the definition of a ternary semigroup. We can see that any semigroup can be reduced to a ternary semigroup. In this paper, we give some auxiliary results which are also necessary for our considerations and characterize the relationship between the (0-)minimal and maximal ordered lateral ideals and the lateral simple and lateral 0-simple ordered ternary semigroups analogous to the characterizations of minimal and maximal left ideals in ordered semigroups considered by Cao and Xu [2].

• Korean Journal of Mathematics
• /
• 제13권2호
• /
• pp.177-182
• /
• 2005

If a semigroup S has no nontrivial congruences then S is either simple or 0-simple.([2]) By contrast with ring theory, not every congruence on a semigroup is associated with an ideal, hence some simple(or 0-simple) semigroup may have a nontrivial congruence. Thus it is a short note for the characterization of a simple(or 0-simple) semigroup that is congruence-free. A semigroup that has no nontrivial congruences is said to be congruence-free.

• 대한수학회논문집
• /
• 제29권1호
• /
• pp.1-8
• /
• 2014

In this paper, we give congruences on an abundant semigroup with a quasi-ideal S-adequate transversal $S^{\circ}$ by the congruence pair abstractly which consists of congruences on the structure component parts R and ${\Lambda}$. We prove that the set of all congruences on this kind of semigroups is a complete lattice.

• Kyungpook Mathematical Journal
• /
• 제54권1호
• /
• pp.123-129
• /
• 2014

In this paper the concepts of pure ideals, weakly pure ideals and purely prime ideals in ordered semigroups are introduced. We obtain some characterizations of pure ideals and prove that the set of all pure prime ideals is topologized.

• 대한수학회보
• /
• 제56권4호
• /
• pp.829-839
• /
• 2019

Let S be a commutative semigroup with 0 and 1. A proper ideal P of S is weakly prime if for $a,\;b{\in}S$, $0{\neq}ab{\in}P$ implies $a{\in}P$ or $b{\in}P$. We investigate weakly prime ideals and related ideals of S. We also relate weakly prime principal ideals to unique factorization in commutative semigroups.

• Korean Journal of Mathematics
• /
• 제21권2호
• /
• pp.171-180
• /
• 2013

We consider a fuzzy semigroup S in a right (or left) reductive semigroup X such that $S(k)=1$ for some $k{\in}X$ and find a faithful representation (or anti-representation) of S by transformations of S. Also we show that a fuzzy semigroup S in a weakly reductive semigroup X such that $S(k)=1$ for some $k{\in}X$ is isomorphic to the semigroup consisting of all pairs of inner right and left translations of S and that S can be embedded into the semigroup consisting of all pairs of linked right and left translations of S with the property that S is an ideal of the semigroup.