Γ-纯整半群

印度数学家Ｍ．Ｋ．Ｓｅｎ和Ｍ．Ｋ．Ｓａｈａ在１９８６年给出了Γ－半群的概念和讨论了Γ－半群的若干性质．本文引入了Γ－正则半群和Γ－纯整半群的概念．并讨论了这两种重要的Γ－半群类的若干特性，最后通过三个有趣的实例说明了纯整Γ－半群类和Γ－纯整半群类是互不包合的及交是非空的．     

Г—纯整半群

印度数学家Ｍ．Ｋ． Ｓｅｎ和Ｍ．Ｋ．Ｓａｈａ在１９８６年给出了Г－半群的概念和讨论了Г－半群的若干性质。本文引入了Г－正则半群和Г－纯整半群的概念。     

正规Ehresmann型wrpp半群

众所周知,Clifford半群是正则半群类中的一类重要半群,本文定义正规 Ehresmann型wrpp半群,它是Clifford半群在wrpp半群类中的推广,给出了此类半群的若干刻划.     

良B-拟Ehresmann半群

设S是一个半群,B是S的一个子带.如果S是一个满足同余条件的B-半富足半群,且对所有的a,b∈S都有aB（a＊）B（b＋）b B（（ab）＋）abB（（ab）＊）,就称S为一个良B-拟Ehresmann半群.本文给出了良B-拟Ehresmann半群的整体表示和标准表示,并作为特殊情形得到了良拟适当半群的结构刻画.     

左半正则纯整群并半群的左半织积结构

作为拟Ｃ－半群的推广,本文定义了左半正则纯整群并群,给出了它的左半织积结构。讨论了两类特殊的右（右）半正则纯整群并半群,得出了左（右）半正则纯整群并半群类与拟Ｃ－半群类之间的关系。     

π－纯整半群的局部化及应用

本文证明π－纯整半群在其幂等元带上的局部化存在且同构于其极大群同态象，由此，得出对应的最小群同余．     

纯整超rpp半群的构造

定义了纯整超rpp半群, 并给出了幂等元集子半群属于由含有不超过3个变量的恒等式决定的带簇的纯整超rpp半群的结构半格分解和标准表示.     

完全α—绝对纯幺半群

本文研究完全α－绝对纯幺半群，给出了这类半群的内部刻划定理。     

正则交半群

进一步研究了正则交半群，引入了纯下在交半群的概念，分别给出了完全正则半群为正则交半群与正交半群的刻划。     

正则纯整群带的算子半群和同余网

正则半群Ｓ的同余格（Ｓ）上的算子Ｋ，ｋ，Ｔ和ｔ定义如下：对于ρ∈Ｓ，ρＫ和ρｋ（ρＴ和ρｔ）分别是与ρ有相同核（迹）的最大和最小同余．我们确定了所有正则纯整群带的同余格上由Ｋ，ｋ，Ｔ和ｔ生成的算子半群．并确定了正则纯整群带上任意同余的同余网．     

Quasi-C-Ehresmann Semigroups and Their Subclasses

We introduce the concept of a quasi-C-Ehresmann semigroup. Some special quasi-C-Ehresmann semigroups will be considered. We will show that the quasi-C-Ehresmann semigroups are special U-semiabundant semigroups and orthodox U-liberal semigroups, which have been recently studied by several authors. Some characterization theorems of this new class of semigroups are obtained. Many results of quasi-C-semigroups in the literature can be extended to quasi-C-Ehresmann Semigroups.     

D-semigroups and constellations

In a result generalising the Ehresmann–Schein–Nambooripad Theorem relating inverse semigroups to inductive groupoids, Lawson has shown that Ehresmann semigroups correspond to certain types of ordered (small) categories he calls Ehresmann categories. An important special case of this is the correspondence between two-sided restriction semigroups and what Lawson calls inductive categories. Gould and Hollings obtained a one-sided version of this last result, by establishing a similar correspondence between left restriction semigroups and certain ordered partial algebras they call inductive constellations (a general constellation is a one-sided generalisation of a category). We put this one-sided correspondence into a rather broader setting, at its most general involving left congruence D-semigroups (which need not satisfy any semiadequacy condition) and what we call co-restriction constellations, a finitely axiomatized class of partial algebras. There are ordered and unordered versions of our results. Two special cases have particular interest. One is that the class of left Ehresmann semigroups (the natural one-sided versions of Lawson’s Ehresmann semigroups) corresponds to the class of co-restriction constellations satisfying a suitable semiadequacy condition. The other is that the class of ordered left Ehresmann semigroups (which generalise left restriction semigroups and for which semigroups of binary relations equipped with domain operation and the inclusion order are important examples) corresponds to a class of ordered constellations defined by a straightforward weakening of the inductive constellation axioms.     

Rees matrix covers for a class of locally U-commutative semigroups

Given the importance of Morita theory of semigroups, we continue the study on the local structure of semigroups. Here we consider a class of nonregular semigroups, called locally U-commutative semigroups having U-local units, containing the classes of locally inverse semigroups, locally adequate semigroups, locally Ehresmann semigroups, and semigroups with local units having locally commuting idempotents. Our aim is to give a Rees matrix covering theorem for such semigroups with a partial McAlister sandwich bundle, and hence to put all the existing results into one context.     

Super rpp semigroups

We study a class of special strongly rpp semigroups, namely, the class of super rpp semigroups. These super rpp semigroups are generalizations of both superabundant semigroups and Clifford semigroups within the class of rpp semigroups. In particular, we prove that a super rpp semigroup is a semilattice of D ^(l)-simple strongly rpp semigroups. Our result not only generalizes a well-known theorem of Clifford in the class of completely regular semigroups but also strengthens some structure theorems obtained by Ren-Shum for superabundant semigroups which are orthodox. Some special super rpp semigroups are considered and discussed.     

Algebras of Ehresmann semigroups and categories

E-Ehresmann semigroups are a commonly studied generalization of inverse semigroups. They are closely related to Ehresmann categories in the same way that inverse semigroups are related to inductive groupoids. We prove that under some finiteness condition, the semigroup algebra of an E-Ehresmann semigroup is isomorphic to the category algebra of the corresponding Ehresmann category. This generalizes a result of Steinberg who proved this isomorphism for inverse semigroups and inductive groupoids and a result of Guo and Chen who proved it for ample semigroups. We also characterize E-Ehresmann semigroups whose corresponding Ehresmann category is an EI-category and give some natural examples.     

Characterizations of Certain Congruences on Orthodox Semigroups

In this paper, we intrnduce the notation pmin,pmin p^min and p^min, by which we describe the trace classes and the kernel classes of general congruence p on orthodox semigronps.Then we have given and proved some equivalent characterizations of special congruences by mean of kernels and traces. On the basis of above-mentioned congruences, we further investigate theirrelations. Some results shout congruences on iverse semigroups are generalized to orthodox semigroups.     

纯正半群上若干同余的刻划(英文)

本文在纯正半群上首先引入了关系ρｍｉｎ,ρｍａｘ,ρｍｉｎ和ρｍａｘ,刻划了纯正半群上一般同余的迹类。然后利用核－迹方法给出了纯正半群上几类特殊同余的等价刻划。在此基础上,进一步研究了各类同余间的相互联系,把逆半群上有关同余的若干结果推广到纯正半群上。     

On algebras of <Emphasis Type="Italic">P</Emphasis>-Ehresmann semigroups and their associate partial semigroups

P-Ehresmann semigroups are introduced by Jones as a common generalization of Ehresmann semigroups and regular \(*\)-semigroups. Ehresmann semigroups and their semigroup algebras are investigated by many authors in literature. In particular, Stein shows that under some finiteness condition, the semigroup algebra of an Ehresmann semigroup with a left (or right) restriction condition is isomorphic to the category algebra of the corresponding Ehresmann category. In this paper, we generalize this result to P-Ehresmann semigroups. More precisely, we show that for a left (or right) P-restriction locally Ehresmann P-Ehresmann semigroup \(\mathbf{S}\), if its projection set is principally finite, then we can give an algebra isomorphism between the semigroup algebra of \(\mathbf{S}\) and the partial semigroup algebra of the associate partial semigroup of \(\mathbf{S}\). Some interpretations and necessary examples are also provided to show why the above isomorphism dose not work for more general P-Ehresmann semigroups.