共查询到20条相似文献,搜索用时 140 毫秒
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具有拟理想正则*-断面的正则半群 总被引:4,自引:1,他引:3
本文提出了具有正则*-断面正则半群的概念,所给出的例子表明具有拟理想正则*-断面的正则半群类真包含了具有拟理想逆断面的正则半群类和正则*-半群类;最后刻画了具有拟理想正则*-断面的正则半群的结构. 相似文献
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称π正则半群S为严格π正则的,若其正则元集RegS是S的理想且为完全正则半群.本文给出了这类半群的一个结构定理.由该定理可推出文献[3,6]的两个结构定理并可简化文献[7]的一个结构定理. 相似文献
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关于Fuzzy完全正则半群 总被引:3,自引:3,他引:0
本文先引入Fuzzy左(Fuzzy右)正则半群的概念,进而讨论Fuzzy左(Fuzzy右)正则半群以及Fuzzy完全正则半群中Fuzzy理想的一些代数性质。 相似文献
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设S是一个正则半群,如果存在一个S的子半群S~*及上的一元运算*满足条件:(1)(?)x∈S,x~*∈S~*∩V(x);(2)(?)x∈S~*,(x~*)~*=x;(3)(?)x,y∈S,(x~*y)~*=y~*x~(**),(xy~*)~*=y~(xx)x~*则称S~*是S的一个正则*_-断面.本文刻画了具有正则*_-断面的正则半群的结构。 相似文献
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本文主要研究模糊正则子半群的度量问题,利用模糊正则子半群度讨论了正则半群的模糊子集是模糊正则半群的程度。首先,文章通过[0,1]上的蕴含给出了模糊正则子半群度的定义。其次,利用正则半群模糊集的(强)水平集得到了模糊正则子半群度的等价刻画。最后,讨论了任意多个模糊子集的交、直积的模糊正则子半群度以及正则半群的模糊子集在同态映射下像与原像的模糊正则子半群度的性质。 相似文献
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Mohan S. Putcha 《Semigroup Forum》1971,3(1):51-57
In this paper we study commutative semigroups whose every homomorphic image in a group is a group. We find that for a commutative
semigroup S, this property is equivalent to S being a union of subsemigroups each of which either has a kernel or else is
isomorphic to one of a sequence T0, T1, T2, ... of explicitly given, countably infinite semigroups without idempotents. Moreover, if S is also finitely generated then
this property is equivalent to S having a kernel. 相似文献
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In this paper we investigate the structure of semigroups with the ideal retraction property i.e., semigroups which are not simple and have the property that each ideal is a homomorphic retract of the semigroup. We present examples to show that the ideal retraction property is neither hereditary nor productive. That this property is preserved by homomorphisms is established for some classes of semigroups, but the general question remains open. The classes of semigroups investigated in this paper are separative semigroups, ideal semigroups, semilattices, cyclic semigroups, nil semigroups, and Clifford semigroups. It is established that a semigroup with zero 0 which is expressible as a direct sum of each ideal and a dual ideal (complement with 0 adjoined) has the ideal retraction property. The converse holds for ideal semigroups, and an example is presented which demonstrates that the converse does not hold in general. 相似文献
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Abstract. In this paper we investigate the structure of semigroups with the ideal retraction property i.e., semigroups which are not
simple and have the property that each ideal is a homomorphic retract of the semigroup.
We present examples to show that the ideal retraction property is neither hereditary nor productive. That this property is
preserved by homomorphisms is established for some classes of semigroups, but the general question remains open.
The classes of semigroups investigated in this paper are separative semigroups, ideal semigroups, semilattices, cyclic semigroups,
nil semigroups, and Clifford semigroups.
It is established that a semigroup with zero 0 which is expressible as a direct sum of each ideal and a dual ideal (complement
with 0 adjoined) has the ideal retraction property. The converse holds for ideal semigroups, and an example is presented which
demonstrates that the converse does not hold in general. 相似文献
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Let S be a semigroup whose set of proper right congruences form a tree. The main theorem is a characterization of those semigroups having this property. In this characterization we draw on the results of Schein and Tamura for commutative semigroups and Kozhukhov for left chain semigroups and Hitzel for nilpotent semigroups. The interested reader should also see the work of Nagy on -semigroups. 相似文献
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Generalizing a property of regular resp. finite semigroups a semigroup S is called E-(0-) inversive if for every a ∈ S4(a ≠ 0) there exists x ∈ S such that ax (≠ 0) is an idempotent. Several characterizations are given allowing to identify the (completely, resp. eventually) regular semigroups in this class. The case that for every a ∈ S4(≠ 0) there exist x,y ∈ S such that ax = ya(≠ 0) is an idempotent, is dealt with also. Ideal extensions of E- (0-)inversive semigroups are studied discribing in particular retract extensions of completely simple semigroups. The structure of E- (0-)inversive semigroups satisfying different cancellativity conditions is elucidated. 1991 AMS classification number: 20M10. 相似文献
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Xiaojiang Guo 《Semigroup Forum》2003,66(3):368-380
The aim of this paper is to study and characterize compact semigroups with the ideal extension property. We establish a characterization of compact semigroups having the ideal extension property. In particular, we completely determine the structure of such semigroups with the property that regular elements form a subsemigroup, and also the structure of such semigroups with precisely one regular D-class. 相似文献
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Guo 《Semigroup Forum》2008,66(3):368-380
Abstract. The aim of this paper is to study and characterize compact semigroups with the ideal extension property. We establish a characterization
of compact semigroups having the ideal extension property. In particular, we completely determine the structure of such semigroups
with the property that regular elements form a subsemigroup, and also the structure of such semigroups with precisely one
regular D-class. 相似文献
19.
Xiaojiang Guo 《Semigroup Forum》2004,69(1):102-112
The aim of this paper is to study the congruence
extension property and the ideal extension property
for compact semigroups. We present a characterization of compact
semigroups with the ideal extension property and prove that each compact semigroup
with the congruence extension property also has the ideal extension property. 相似文献
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Mohan S. Putcha 《Semigroup Forum》1973,6(1):12-34
The purpose of this paper is to develop a general theory of semilattice decompositions of semigroups from the point of view
of obtaining theorems of the type: A semigroup S has propertyD if and only if S is a semilattice of semigroups having property β. As such we are able to extend the theories of Clifford
[3], Andersen [1], Croisot [5], Tamura and Kimura [14], Petrich [9], Chrislock [2], Tamura and Shafer [15], Iyengar [7] and
Weissglass and the author [10]. The root of our whole theory is Tamura's semilattice decomposition theorem [12, 13]. Of this,
we give a new proof.
The results of this paper were obtained by the author between January and July of 1971, while an undergraduate at the University
of California, Santa Barbara. 相似文献