On Some Monogenic Semigroups with an Associate Subgroup

Let S be any semigroup and a, s ∈ S. If a = asa, then s is an associate of a. A subgroup G of S is an associate subgroup of S if every a ∈ S has a unique associate a* in G. It turns out that G = H _z for some idempotent z, the zenith of S. The mapping a → a* is a unary operation on S. We say that S is monogenic if S is generated, as a unary semigroup, by a single element.

We embark upon the problem of the structure of monogenic semigroups in this sense by characterizing monogenic ones belonging to completely simple semigroups, normal cryptogroups, orthogroups, combinatorial semigroups, cryptic medial semigroups, cryptic orthodox semigroups, and orthodox monoids. In each of these cases, except one, we construct a free object. The general problem remains open.     

On residual finiteness of direct products of algebraic systems

It is well known that if two algebraic structures A and B are residually finite then so is their direct product. Here we discuss the converse of this statement. It is of course true if A and B contain idempotents, which covers the case of groups, rings, etc. We prove that the converse also holds for semigroups even though they need not have idempotents. We also exhibit three examples which show that the converse does not hold in general.      

Large and high subgroup

It is proved that a high subgroup of a large subgroup is closed in a high subgroup of the group itself. Also a necessary and sufficient condition for a subgroup to be a pureabsolute summand is obtained.     

On the Supersolvability of QCLT-Groups

ＯｎｔｈｅＳｕｐｅｒｓｏｌｖａｂｉｌｉｔｙｏｆＱＣＬＴ－ＧｒｏｕｐｓＷａｎｇＰｉｎｃｈａｏ（王品超）；ＬｕＺａｉｐｉｎｇ（路在平）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＱｕｆｕＮｏｒｍａｌＵｎｉｖｅｒｓｉｔｙ，Ｑｕｆｕ，Ｓｈａｎｄｏｎｇ，...     

关于Ky Fan的一个猜想

设ｆ（ｚ）为单位圆上的规范化的单叶凸像函数，Ｌ（Ｈ）为复Ｈｉｌｂｅｒｔ空间Ｈ上的Ｂａｎａｃｈ算子代数。本文证明了对于Ｌ（Ｈ）中双重可换的真收缩算子Ｔｔ（ｉ＝１，２），ｆ（Ｔ１）与ｆ（Ｔ２）的凸线性组合一定具有形式ｆ（Ｔ），此处Ｔ为Ｌ（Ｈ）中的真收缩算子，同时我们通过一简单例子说明“Ｔｔ双重可换”的条件是不能去掉的，这便回答了由ＫｙＦａｎ提出的一个问题。     

关于模糊群的上确界性质的几个结果及其应用

研究了模糊子群的上确界性质并给出了模糊具有上确界性质的充要条件,利用它研究了循环群模糊子群的结构。最后,本文研究了一种比上确界性质弱一些的条件,在该条件下模糊可以具有好的性质。     

On[m,P_1~(a_1),P_2~(a_2),…,P_s~(a_s)]Index Type Groups

Ｏｎ［ｍ，Ｐ_１~（ａ_１）,Ｐ_２~（ａ_２）,…,Ｐ_ｓ~（ａ_ｓ）］ＩｎｄｅｘＴｙｐｅＧｒｏｕｐｓＬｉＸｉａｎｈｕａ（黎先华）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＧｕｉｚｈｏｕＮｏｒｍａｌＵｎｉｖｅｒｓｉｔｙ，Ｇｕｉｙａｎｇ，５５０００１）Ａ...     

序半群的广义直觉模糊理想

介绍序半群中具有边界值(α,β)的直觉模糊左理想和直觉模糊双理想的概念,对其性质进行了探讨,并通过有边界值(α,β)的直觉模糊左理想和直觉模糊双理想,对左正则和正则序半群的特征进行了研究.     

群G的反模糊子群

给出一个群G的反模糊子群和正规反模糊子群的概念,这些定义不同于Rosenfeld和吴望名等的定义,本文还讨论了正规反模糊子群的一些性质及模糊商群等。     

基于模糊不变子群的上、下近似

研究群中集合的粗糙近似问题。利用分解定理和表现定理,定义了群中集合关于模糊不变子群的上、下近似,并给出了近似算子的性质。证明了子群的上、下近似在同态映射下的不变性质。     

On S~i-quasinormal Subgroups

The objective of this paper is to invertigate the influence of maximal subgroups on the structure of a finite group.We introduce a concept of "normality" based on the permuting of certain subgroups.This concept leads to a generalization of Asaad and Shaalan's result.     

有限群的Fuzzy拟正规子群和Fuzzy次正规子群

讨论有限群的Fuzzy拟正规子群和Fuzzy次正规子群的一些性质。     

On the equations defining irreducible algebraic groups

Abstract

We consider five known problems concerning positive laws in groups. One of them has a counterexample, the others are open in general. It is shown that three of the problems are equivalent and all of them have a positive solution in the class of locally graded groups.     

模糊商群的推广

引入关于一个子群的正规模糊子集概念，研究正规模糊子集的一些性质，并在此基础上将模糊商群做了自然推广，最后建立群同态下正规模糊子集的对应定理。     

关于Clifford半群上的fuzzy同余

利用半群fuzzy同余的概念,讨论一类特殊的完全正则半群,即Clifford半群上的fuzzy同余.研究该类半群上fuzzy同余的性质.在此基础上,给出Clifford半群上fuzzy同余的性质和特征,得到Cllifford半群上fuzzy同余为fuzzy消去同余的充要条件.     

由格蕴涵代数诱导的伴随半群

给出由格蕴涵代数诱导出的伴随半群及有关概念 ,详细讨论伴随半群中的元素即格蕴涵代数的左映射的性质 ,得到它们的几个等价条件。最后讨论由格蕴涵代数诱导的两个双格半群与伴随半群之间的关系 ,并证明这些半群是幂等的当且仅当它们是由格 H蕴涵代数所诱导     

特征单群的模糊子群构造

通过研究特征单群的合成群列和子群链的构造特点,得出了能够反映特征单群的模糊子群构造特征的极大Fuzzy子群的阶和等价类数以及Fuzzy子群的等价类数的公式.