QF环性质向扩环上的传递

设环Ａ是环Ｂ的扩环（记作Ａ／Ｂ），Ｂ是ＱＦ环，在本文中我们将证明在以下四种情形下Ａ也是ＱＦ环：（１）_ＢＡ是有限生成自由的且Ａ／Ｂ是投射扩张．（２）Ａ／Ｂ是Ｆｒｏｂｅｎｉｕｓ的．（３）Ａ／Ｂ是可离且平坦的．（４）Ａ／Ｂ是Ｈ－可离的．     

二次系统的二重极限环和以无限大分界线环分支出两个极限环的例子

二次系统的二重极限环和以无限大分界线环分支出两个极限环的例子沈伯骞，何平（辽宁师范大学数学系，大连１１６０２２）（辽宁警官专科学校，大连１１６０３３）ＥＸＡＭＰＬＥＳＯＦＯＮＥＤＯＵＢＬＥＬＩＭＩＴＣＹＣＬＥＯＲＴＷＯＳＩＮＧＬＥＬＩＭＩＴＣＹＣＬＥ...     

模的嵌入问题

本文首先在文［１］工作的基础上进一步讨论了“每个有限生成模可嵌入到自由模”的环类，这类环称为ＦＧＦ－环，接着引进了一类包括ＦＧＦ－环和拟完全环的环类，这类环称作ＦＧＦＦ－环，即“每个有限生成平坦模可嵌入到自由模中”，讨论了这类环的一些特征性质及其与已知一些重要环类间的关系．这一类环的背景是文［１－６］．本文还回答了文［５］的一个问题．     

gr—正则环和矩阵环的gr—正则性

本文主要证明了（１）当Ｇ是有限群时，Ｇ－型分次环Ｒ是ｇｒ－正则的当且仅当Ｒ＃Ｇ是正则的当且仅当ＭＧ（Ｒ）是ｇｒ－正则的当且仅当对每个λ∈Ｇ和Ｇ的任意非空子集Ｈ和Ｆ，ＭＨ×Ｆ（Ｒ）的每个矩阵都有１－逆。（２）当Ｇ是任意群，Ｇ－型分次环Ｒ是反ｇｒ－正则的当且仅当Ｆ（Ｒ＃Ｇ）是反正则的当且仅当对每个λ∈Ｇ和Ｇ的任意非空子集Ｈ和Ｋ，ＦＭＨ×Ｆ（Ｒ）的每个矩阵有２－逆当且仅当ＦＭＧ（Ｒ）是ｇｒ－反正则的。     

关于NF-环的构造

研究了无限的ＮＦ－环及有限的ＮＦ－环，并且给出了有限ＮＦ－环的构造．     

关于分次环的分次性质和非分次性质

本文证明了对有限群分次环Ｒ而言,下列条件等价：（１）Ｒ是左ｇｒ－自内射环（左ｇｒ－ＰＦ环,左ｇｒ－ＱＦ环,左ｇｒ－线性紧环）．（２）Ｒ是左自内射环（左ＰＦ环,左ＱＦ环,左线性紧环）．（３）Ｒ＃Ｇ^*是左自内射环（左ＰＦ环,左ＱＦ环,左线性紧环）．     

右IF－环及凝聚环的挠理论

本文研究了右ＩＦ－环的性质，证明出环Ｒ是右ＩＦ－环当且仅当Ｒ是左凝聚环，并且是平坦模；由此证明出右ＩＦ－环与左ＧＱＦ－环是等价的，其次应用右ＩＦ－环研究了凝聚环的挠理论性质，证明出凝聚环与Ｔ－凝聚环的关系。     

gr－正则环和矩阵环的gr－正则性

本文主要证明了（１）当Ｇ是有限群时，Ｇ－型分次环Ｒ是ｇｒ－正则的当且仅当ＲＧ是正则的当且仅当Ｍ＿Ｇ（Ｒ）是ｇｒ－正则的当且仅当对每个和Ｇ的任意非空子集Ｈ和Ｆ，Ｍ＿（ＨＸＦ）（Ｒ）的每个矩阵都有１－逆。（２）当Ｇ是任意群，Ｇ－型分次环只是反ｇｒ－正则的当且仅当Ｆ是反正则的当且仅当对每个和Ｇ的任意作非空子集Ｈ和Ｋ，ＦＭ＿（Ｈ×Ｆ）（Ｒ）的每个矩阵有２－逆当且仅当ＦＭ＿Ｇ（Ｒ）是ｇｒ－反正则的。     

右IF－环及凝聚环的挠理论

本文研究了右ＩＦ－环的性质，证明出环Ｒ是右ＩＦ－环当且仅当Ｒ是左凝聚环，并且是平坦模；由此证明出右ＩＦ－环与左ＧＱＦ－环是等价的，其次应用右ＩＦ－环研究了凝聚环的挠理论性质，证明出凝聚环与Ｔ－凝聚环的关系。     

IF环和拟ZIF环

本文定义了拟ＺＩＦ环．研究了ＩＦ环与拟ＺＩＦ环的结构．进一步地，讨论了ＩＦ环与拟ＺＩＦ环的关系，并用拟ＺＩＦ环刻划了ＩＦ环．     

环上线性群的子群结构

本文主要讨论欧氏整环上线性群一类子群的结构,并获得其一类极大子群,     

Regular Rings With Generalized s-Comparability

In this paper, we investigate generalized s-comparability over regular rings. These also give generalizations of the corresponding results over regular rings satisfying general comparability.AMS Subject Classification (1991) 16A30 16E50     

第n根性质与根环

令E为 (MR)的自同态环 ,本文首先证明了MR 有第n根性质的充要条件是EE 有第n根性质 ,由此引进了根环的概念 ,并研究了根环的性质。特别地我们证明了如nA nB且A拟内射 ,则A B .     

Moduln über Streckungsringen

The aim of this paper is to prove that many homological properties and estimates of the discrete straightening ring still remain valid for the straightening ring itself. E.g. Cohen-Macaulay property, generalised Cohen-Macaulay property and Serre condition (S_n) (the latter for unmixed discrete straightening rings) transfer. The main technical tool is a further development of a spectral sequence argument well known in the case of associated graded rings.     

Triangulated Categories and the Ziegler Spectrum

The relationship between the Ziegler spectrum of (the category of modules over) a ring and the Ziegler spectrum of its derived category is investigated. Over von Neumann regular rings and hereditary rings the spectrum of the derived category is a disjoint union of copies of the spectrum of the ring but in general there are further indecomposable pure-injective objects of the derived category. Presented by A. Verschoren Mathematics Subject Classifications (2000) Primary: 18E30; secondary: 03C60.     

A New Proof that “Krull implies Zorn”

In the present note we give a direct deduction of the Axiom of Choice from the Maximal Ideal Theorem for commutative rings with unit. Mathematics Subject Classification: 03E25, 04A25, 13A15.     

Generalized Stable Exchange Rings

In this paper, we investigate diagonal reductions of matrices over generalized stable exchange rings. We show that every regular matirx over generalized stable exchange rings with stable range 2 admits power diagonal reduction.AMS Subject Classification (1991): 16A30 16E50This work was supported by the National Natural Science Foundation of China.     

On the structure of indecomposable injective modules 1

For a ring R, the following two conditions are equivalent:.

(1) If E is an indecomposable injective right R-module, then End E_R is a field (not necesarily commutative).

(2) Every co-irreducible rigtht ideal is critical.

Since (2) has been characterized ideal-theoretically, this amounts to an ideal-theoretical characterization of (1). These rings come up to the study of (QI) rings in which every quasi-injective module is injective.     

A New Look at the Burnside-Schur Theorem

The famous Burnside–Schur theorem states that every primitivefinite permutation group containing a regular cyclic subgroupis either 2-transitive or isomorphic to a subgroup of a 1-dimensionalaffine group of prime degree. It is known that this theoremcan be expressed as a statement on Schur rings over a finitecyclic group. Generalizing the latter, Schur rings are introducedover a finite commutative ring, and an analogue of this statementis proved for them. Also, the finite local commutative ringsare characterized in permutation group terms. 2000 MathematicsSubject Classification 20B10, 20B15, 05E99.