Artin模的自同态环

本文讨论Ａｒｔｉｎ模的自同态环何时为半完全环的问题．对于Ａｒｔｉｎ模ＭＲ，本文证明了：（１）若Ｍ是非单的直和不可分解模，则ｓｏｃＭ为见的小子模；（２）对任意Ａｒｔｉｎ模Ｍ及任意Ａｒｔｉｎ半单模Ｌ，ＥｎｄＲ（ＭＬ）为半完全环的充要条件为ＥｎｄＲ（Ｍ）是半完全环．本文还证明了（直和不可分解的）拟投射Ａｒｔｉｎ模的自同态环为（局部环）半准素环．而对于非零的Ａｒｔｉｎ投射模Ｐ，“Ｐ直和不可分解”等价于“Ｐ和不可分解”．     

关于正则模的自同态环

本文研究正则模Ｐ的自同态环Ｓ,主要给出使Ｓ的稳定秩为１的Ｐ的几个充分条件．     

交换环上矩阵保逆的模自同态

本文刻划交换环上全矩阵模保矩阵逆的自同态。     

有限置换模自同态环的可分性质

设Q是有限置换右R模,则End_R(Q)是可分环当且仅当对所有A,B∈FP(Q),A AA B B B A≤ B或 B≤A,作为应用得到了 End_R(P Q)是可分环当且仅当End_R P和End_R Q为可分环,其中P,Q为有限置换右R模。     

正规环的Fuzzy双侧理想

本文首先提出正规环的Fuzzy双侧理想的定义,讨论了Fuzzy双侧理想和Fuzzy理想之间的关系,给出对环、Fuzzy对环、左(右)零环等概念,并在正规环中研究了它们的性质。最后在超正规环和完全正规环中研究了Fuzzy双侧理想和Fuzzy理想,得出一些有趣的结果。     

有限置换模自同态环的可分性质

设Q是有限置换右R模,则EndR(Q)是可分环当且仅当对所有A,B∈FP(Q),A A≌A B≌B B A≤ B或B≤ A.作为应用得到了EndR(P Q)是可分环当且仅当EndRP和EndRQ为可分环,其中P,Q为有限置换右R模.     

PI—环上有限生成模的自同态的一个注记

本文将交换环上有限生成模的单自同态的有关结果推广到ＰＩ－环上,得到如下类似结果。     

一类Artin模的自同态环的K0群

本文确定了一类Ａｒｔｉｎ模的自同态环的Ｋ０群，并给出Ａｒｔｉｎ模的几条有趣的特征性质。     

交换环上全矩阵模的保幂等自同态

本文对交换环 R 上全矩阵模 M_n(R)的保幂等自同态进行了刻划,推广了[1]与[2]的工作.     

A companion ideal of a multiplication module

Let M _R be a faithful multiplication module, where R is a commutative ring. As defined by Anderson, this ideal has proved to be useful in studying multiplication modules. First of all a cancellation law involving M and the ideals contained in is proved. Among various applications given, the following result is proved:: There exists a canonical isomorphism from onto such that for any ( Hom _R(M,M), x ( M, a ( (M), (xa) = x.(()(a). As an application of this later result it is proved that M is quasi-injective if and only if (M) is quasi-injective.     

Rickart Modules

The concept of right Rickart rings (or right p.p. rings) has been extensively studied in the literature. In this article, we study the notion of Rickart modules in the general module theoretic setting by utilizing the endomorphism ring of a module. We provide several characterizations of Rickart modules and study their properties. It is shown that the class of rings R for which every right R-module is Rickart is precisely that of semisimple artinian rings, while the class of rings R for which every free R-module is Rickart is precisely that of right hereditary rings. Connections between a Rickart module and its endomorphism ring are studied. A characterization of precisely when the endomorphism ring of a Rickart module will be a right Rickart ring is provided. We prove that a Rickart module with no infinite set of nonzero orthogonal idempotents in its endomorphism ring is precisely a Baer module. We show that a finitely generated module over a principal ideal domain (PID) is Rickart exactly if it is either semisimple or torsion-free. Examples which delineate the concepts and results are provided.     

Commutative rings whose proper ideals are direct sums of uniform modules

An interesting result, obtaining by some theorems of Asano, Köthe and Warfield, states that: “for a commutative ring R, every module is a direct sum of uniform modules if and only if R is an Artinian principal ideal ring.” Moreover, it is observed that: “every ideal of a commutative ring R is a direct sum of uniform modules if and only if R is a finite direct product of uniform rings.” These results raise a natural question: “What is the structure of commutative rings whose all proper ideals are direct sums of uniform modules?” The goal of this paper is to answer this question. We prove that for a commutative ring R, every proper ideal is a direct sum of uniform modules, if and only if, R is a finite direct product of uniform rings or R is a local ring with the unique maximal ideal ? of the form ? = U⊕S, where U is a uniform module and S is a semisimple module. Furthermore, we determine the structure of commutative rings R for which every proper ideal is a direct sum of cyclic uniform modules (resp., cocyclic modules). Examples which delineate the structures are provided.     

On some generalizations of the radical of an ideal and the radical of a submodule

In the paper, the notions of radical of an ideal and radical of a submodule are generalized and described.     

环模上的比较结构

本文推广［１］中主要结论,得到了自同态环的。比较性与模的比较结构间的关系．进一步地,我们把环上的比较结构推广到了模上,并证明了模上的比较性是直和分量不变的．最后,给出了环比较与模比较之间的一类等价关系．