自然序Dubreil-Jacotin富足半群

本文考虑Ｄｕｂｒｅｉｌ－Ｊａｃｏｔｉｎ富足半群,给出若干特征后,建立了自然序Ｄｕｂｒｅｉｌ－Ｊａｃｏｔｉｎ富足半群的结构,作为应用,给出了具有正则性条件的自然序Ｄｕｂｒｅｉｋｌ－Ｊａｃｏｔｉｎ富足半群的结构,并将结果推广到具有最大幂等元的自然序的偏序富足半群上。     

Structure globale des extensions regulieres galoisiennes

A natural characterization of known types of inverse transversal leads to the introduction of several new types, which we characterize in a similar natural way. Relations between the various types produce a general classification. We also determine for which types of inverse transversal considered the congruence extension property holds.     

INVERSE TRANSVERSALS ARE MUTUALLY ISOMORPHIC

It has been suspected for some time that if a regular semigroup S has an inverse transversal then all inverse transversals of S are isomorphic. Here we give a proof of this fact.     

完全单半群及完全正则半群的逆断面

指出完全单半群Ｓ的任何一个Ｆ－类是逆断面,且为Ｑ－逆断面,而Ｓ的任何一个逆断面必是一个Ｆ－类,因而所有逆断面同构。并且给出完全正则半群的逆断面存在的充要条件。     

Naturally ordered regular semigroups with an inverse monoid transversal

The notion of an inverse transversal of a regular semigroup is well-known. Here we investigate naturally ordered regular semigroups that have an inverse transversal. Such semigroups are necessarily locally inverse and the inverse transversal is a quasi-ideal. After considering various general properties that relate the imposed order to the natural order, we highlight the situation in which the inverse transversal is a monoid. The regularity of Green’s relations is also characterised. Finally, we determine the structure of a naturally ordered regular semigroup with an inverse monoid transversal.     

Associate inverse subsemigroups of regular semigroups

By an associate inverse subsemigroup of a regular semigroup S we mean a subsemigroup T of S containing a least associate of each x∈S, in relation to the natural partial order ≤ _S . We describe the structure of a regular semigroup with an associate inverse subsemigroup, satisfying two natural conditions. As a particular application, we obtain the structure of regular semigroups with an associate subgroup with medial identity element. Research supported by the Portuguese Foundation for Science and Technology (FCT) through the research program POCTI.     

<Emphasis Type="Italic">E</Emphasis>-inversive Dubreil-Jacotin semigroups

Using group congruences, we obtain necessary and sufficient conditions for an ordered E-inversive semigroup to be a Dubreil-Jacotin semigroup. We also determine when such a semigroup is naturally ordered. In particular, when the subset of regular elements is a subsemigroup it contains a multiplicative inverse transversal.     

具有左简纯正断面的正则半群

本文引入并研究了左简纯正断面, 得到了与之相关的若干刻画; 推广并丰富了Blyth 和AlmeidaSantos 于1996 年得到的关于左简逆断面及Kong 于2007 年得到的关于纯正断面的相关结果; 同时,给出了具有左简纯正断面的正则半群的结构定理.     

On generalized inverse transversals

Let S be a regular semigroup, S° an inverse subsemigroup of S.S° is called a generalized inverse transversal of S, if V（x）∩S°≠Ф. In this paper, some properties of this kind of semigroups are discussed. In particular, a construction theorem is obtained which contains some recent results in the literature as its special cases.     

П正则半群的幂等元同余类

本文分别给出П正则半群的幂等元同余类和Пｏｒｔｈｏｄｏｘ半群［１］的幂等元同余类的П正则性刻画．其次，证明П逆半群或完全П正则半群Ｓ的幂等元同余类是Ｓ的П正则子半群．最后讨论ｏｒｔｈｏｄｏｘ半群的幂等元同合类的正则性．     

具有E—逆断面的正则半群的结构定理

讨论了具有E－逆断面的正则半群的性质;并给出了具有E－逆断面的正则半群的一种结构定理。     

具有Clifford断面的纯正半群

本文研究有Clifford断面的纯正半群.为了获得主要的结构定理，证明了纯正半群有群断面当且仅当它是矩形群;利用半格和矩形带，建立了有Clifford断面的纯正半群的结构.     

Split quasi-adequate semigroups

The so-called split IC quasi-adequate semigroups are in the class of idempotent-connected quasi-adequate semigroups. It is proved that an IC quasi-adequate semigroup is split if and only if it has an adequate transversal. The structure of such semigroup whose band of idempotents is regular will be particularly investigated. Our obtained results enrich those results given by McAlister and Blyth on split orthodox semigroups.     

Abundant semigroups with a multiplicative quasi-adequate transversal

The concept of quasi-adequate transversals is introduced. Some properties and characterizations for abundant semigroups with a multiplicative quasi-adequate transversal are obtained. In particular, a structure theorem for such abundant semigroups is given. Finally, some special cases are considered. This research was partially supported by the National Natural Science Foundation of China (No. 10571077) and the Natural Science Foundation of Gansu Province (No. 3ZS052-A25-017).     

具有逆断面的正规纯正半群

A normal orthodox semigroup is an orthodox semigroup whose idempotent elements form a normal band.We deal with congruces on a normal orthodox semigroup with an iverse transversal .A structure theorem for such semigroup is obtained.Munn(1966)gave a fundamental inverse semigroup Following Munn‘s idea ,we give a fundamental normal orthodox semigroup with an inverse transversal.