分次Morita对偶，Morita对偶与Smash积

设Ｃ和ｒ都是群，是Ｇ－型分次环，是Γ－型分次环．是双分次模，Ｒ＃Ｇ是Ｒ的Ｓｍａｓｈ积，Ａ＃Γ是Ａ的Ｓｍａｓｈ积。令Ｗ＝（＿ｇＵ＿（σ－１））＿（ｇ，σ）即（ｇ，σ）位置取＿ｇＵ＿（σ－１）的元素的｜Ｇ｜×｜Γ｜矩阵的全体组成的集合，且每个矩阵的每行和每列的非零元只有有限个，按矩阵运算，Ｗ构成（Ｒ＃６，Ａ＃Γ）双模。则＿ＲＵ＿Ａ定义了一个分次Ｍｏｒｉｔａ对偶当且仅当＿（Ｒ＃Ｇ）Ｗ＿（Ａ＃Γ）定义了一个Ｍｏｒｉｔａ对偶。     

Morita对偶和Smash积

设G是有限群,e为G的单位元,R=是有单位元的G-型分次环,T=R_e,R_U是极小内射余生成子.本文中,我们证明了R有左Morita对偶当且仅当Smash积R#G有左Morita对偶.设H是G的(正规)子群,若R有左Morita对偶,则R~((H))#H(R_((G/H))#(G/H))有左Morita对偶。当R是强分次环时,T有左Morita对偶当且仅当R有左Morita对偶当且仅当R#G有左Morita对偶.     

广义幂级数环的PP性质

作为幂级数环的推广,Ｒｉｂｅｎｂｏｉｍ引入了广义幂级数环的概念．设Ｒ是有单位元的交换环,（Ｊ,≤）是严格全序半群．本文中我们证明了如下结果：（１）广义幂级数环 ［［Ｒｓ］］是ＰＰ－环当且仅当Ｒ是ＰＰ－环且Ｂ（Ｒ）的任意 Ｓ－可标子集Ｃ在Ｂ（Ｒ）中有最小上界;（２）如果对任意ｓ∈Ｓ都有０≤ｓ,则［［Ｒｓ,≤］］是弱ＰＰ－环当且仅当Ｒ是弱ＰＰ－环．我们还给出了一个例子说明交换的弱ＰＰ－环可以不是ＰＰ－环．     

广义幂级数环上的PS模

Let R be a commutative ring and(S,≤)a strictly totally ordered monoid which satisfies the condition that 0≤s for every s ∈ S,In this paper we show that if RM is a PS-module,then the module [[M^s,≤]]of generalized power series over M is a PS [[R^s,≤]]-module.     

带Morita对偶的偏序集环

设Ｒ是有１的结合环，Ｉ是任意偏序集，ＲＩ是Ｒ上Ｉ的偏序集环．本文考虑了带对偶的偏序集环，得到：ＲＩ带Ｍｏｒｉｔａ对偶当且仅当Ｒ带Ｍｏｒｉｔａ对偶．推广了已有的在Ｒ是有限偏序集时的有关结果     

Gr—Morita对偶

[1,2]中讨论了G-分次（R-A）-双模RUA导出一个Gr-Morita对偶与Morita对偶的关系,本将进一步给出G-型分次（R-S）-双模RUS定义一个Gr-Morita对偶的充要条件。     

广义幂级数环的本质理想和非奇异性

本文研究了广义幂级数环与其系数环在本质理想和非奇异性上的关系.利用本质理想的定义和性质,得到了广义幂级数环的左理想为本质左理想的菪干充分必要条件.在此基础上,给出了广义幂级数环为左非奇异环的充分必要条件.     

半群分次环上的Morita对偶

本文主要研究了半群分次环上的Morita对偶问题,讨论了半群分次模范畴上满足某种条件的对偶函子与双分次双模之间的等价关系.得到重要定理：半群双分次$R$-$A$双模$Q$定义一个半群分次Morita对偶当且仅当${}_RQ_A$是分次忠实平衡的,且${rm Ref}({}_RQ)$, ${rm Ref}(Q_A)$对分次子模和分次商模是封闭的.     

投射自由环的Morita特征

本文研究投射自由环的Ｍｏｒｉｔａ特征,证明了投射自由环具有Ｍｏｒｉｔａ不变性．     

整环上广义幂级数环的分解性质

设A(て)B是整环的扩张,(S,≤)是满足一定条件的严格偏序幺半群,[[BS,≤]]是整环B上的广义幂级数环.本文研究整环[Bs,≤]]和{f∈[[Bs,≤]]|f(0)∈A}的ACCP条件和BFD性质.结果表明,整环{f∈[[BS,≤]]|f(0)∈A}的分解性质不仅依赖于A和B的分解性质以及U(A)和U(B),而且还依赖于幺半群S的分解性质.该结果能够构造出具有某种分解性质的整环的新例子.     

Morita Duality for the Rings of Generalized Power Series

Let A, B be associative rings with identity, and (S, ≤) a strictly totally ordered monoid which is also artinian and finitely generated. For any bimodule _A M _B , we show that the bimodule _{[[ AS,≤ ]]}[M ^{S ,≤}]_{[[ BS, ≤ ]]} defines a Morita duality if and only if _A M _B defines a Morita duality and A is left noetherian, B is right noetherian. As a corollary, it is shown that the ring [[A ^{S ,≤}]] of generalized power series over A has a Morita duality if and only if A is a left noetherian ring with a Morita duality induced by a bimodule _A M _B such that B is right noetherian. Received April 13, 1999, Accepted December 12, 1999     

广义幂级数环上Morita Context环的稳定条件

In this paper, we show that if rings A and B are （s, 2）-rings, then so is the ring of a Morita Context（[[A^S,≤]],[[B^S,≤]],[[M^S,≤]],[[N^S,≤]],ψ^S,Ф^S）of generalized power series. Also we get analogous results for unit 1-stable ranges, GM-rings and rings which have stable range one. These give new classes of rings satisfying such stable range conditions.     

PP-Rings of Generalized Power Series

Abstract As a generalization of power series rings, Ribenboim introduced the notion of the rings of generalized power series. Let R be a commutative ring, and (S, ≤) a strictly totally ordered monoid. We prove that (1) the ring [[R ^S,≤]] of generalized power series is a PP-ring if and only if R is a PP-ring and every S-indexed subset C of B(R) (the set of all idempotents of R) has a least upper bound in B(R) and (2) if (S, ≤) also satisfies the condition that 0 ≤s for any s∈S, then the ring [[R ^S,≤ ]] is weakly PP if and only if R is weakly PP. Research supported by National Natural Science Foundation of China, 19501007, and Natural Science Foundation of Gansu, ZQ-96-01     

有足够幂等元的群分次环上的Morita对偶

首先定义了具有足够幂等元的群分次环的Ｓｍ ａｓｈ 积并讨论其性质,其次,借助Ｓｍ ａｓｈ 积给出了这类分环上的分次Ｍｏｒｉｔａ对偶的刻划．     

Duality for Weakly Co-Hopfian and Generalized Hopfian Modules

Abstract

Duality like connections are established for generalized Hopfian modules and weakly co-Hopfian modules. A generalization of ring Hopficity is also introduced and this concept is studied for matrix rings.     

广义幂级数代数的滤链维数

In this paper, we study the properties of generalized power series modules and the filtration dimensions of generalized power series algebras. We obtain that [[△S,≤]]- gfd([[AS,≤]]) =△-gfd(A) if A is an R-module where R is a perfect and coherent commutative algebra, and(R, ≤) is standardly stratified.