关于基本可数生成子模的扩张性

称左R-模M是ecg-扩张模,如果M的任意基本可数生成子模是M的直和因子的基本子模.在研究了ecg-扩张模的基本性质的基础上,本文证明了对于非奇异环R,所有左R-模是ecg-扩张模当且仅当所有左R-模是扩张模.同时我们还用ecg-拟连续模刻画了Noether环和Artin半单环.     

Noether环的几点注记

本文利用特征模给出了Ｎｏｅｔｈｅｒ环的一些充分必要条件，并由此讨论了Ｎｏｅｔｈｅｒ环上的内射模与平坦模的一些性质     

具有d-Koszul子模滤的分次模

引入了弱d-Koszul模,它是d-Koszul模的一种自然推广.设A是d-Koszul代数,M是有限生成的分次A-模,则M是弱d-Koszul模当且仅当M具有子模滤 0(∪) U0(∪)U1(∪)…(∪)Up=M,使得所有的A-模 Ui/Ui-1是d-Koszul模.设M为一个弱d-Koszul模,则作为分次Ext*A(A0,A0)-模,其Koszul对偶,ε(M)=Ext*A(M,A0)是由0次生成的.     

具有d-Koszul子模滤的分次模

引入了弱d-Koszul模,它是d-Koszul模的一种自然推广．设A是d-Koszul代数,M是有限生成的分次A-模,则M是弱d-Koszul模当且仅当M具有子模滤:0(?)U0(?)U1(?)…(?)Up=M,使得所有的A-模Ui／Ui-1是d-Koszul模．设M为一个弱d-Koszul模,则作为分次ExtA*(A0,A0)-模,其Koszul对偶:ε(M)=ExtA*(M,A0)是由0次生成的．     

局部Noether模的相对连续性特征

设M是左R-模,本文证明了M是局部Noether的当且仅当σ[M]中的任意M-内射左R-模的直和是S∧2-连续的（S∧2-拟连续的）。     

具有性质（P）的环的同调维数

主要研究具有性质（P）环的同调维数,所得的结果推广了[1]的结果。     

Noether环理想的性质

Noether交换环是一类非常重要的环,本文主要对Noether交换环进行了研究和讨论,得到了Noether交换环、Noether整环的若干性质;并推广了文[1]中的部分结果.     

环的广义Noether性(英)

众所周知,环R是右Noether的当且仅当任意内射右R-模的直和是内射的．本文我们将用Ne-内射模和U-内射模来刻画Ne-Noether环和U-Noether环．     

具有极大乘积的型理想阵列空间的结构和循环模性质

设I1,…,In是有限域上双周期理想,称它们具有极大乘积,如果本文决定了具有极大乘积的型理想I1,…;In的结构,并证明了乘积空间G(I1*…*In）是循环模.     

关于所有子模是纯子模的平坦模

引进了一新模类-完全平坦模(每一个商模平坦).并得到了:令M是平坦左R-模,RM是完全平坦模当且仅当RM的所有子模是纯的当且仅当每一个右R-模A是M-平坦的.同时本文用完全平坦模刻画了V.N.正则环.     

Comultiplication submodules of multiplication modules

Abstract

All rings are commutative with identity, and all modules are unital. The purpose of this work is to investigate comultiplication submodules of multiplication modules. Various properties of this class of submodules are considered. Sufficient conditions for the sum and intersection of a finite collection of comultiplication submodules to be a comultiplication submodule are also given.     

On the Countability of Noetherian Dimension of Modules

Abstract

It is shown that a module M has countable Noetherian dimension if and only if the lengths of ascending chains of submodules of M has a countable upper bound. This shows in particular that every submodule of a module with countable Noetherian dimension is countably generated. It is proved that modules with Noetherian dimension over locally Noetherian rings have countable Noetherian dimension. We also observe that ω^ω is a universal upper bound for the lengths of all chains in Artinian modules over commutative rings.     

On Serial Noetherian Rings

It is well known that every serial Noetherian ring satisfies the restricted minimum condition. In particular, following Warfield (1975 Warfield , R. B. ( 1975 ). Serial rings and finitely presented modules . J. Algebra 37 : 187 – 222 . [CSA] [CROSSREF] [Crossref], [Web of Science ®] , [Google Scholar]), such a ring is a direct sum of an Artinian ring and hereditary prime rings. The aim of this note is to show that every serial ring having the restricted minimum condition is Noetherian.     

The Euler Class Group of a Noetherian Ring

For a commutative Noetherian ring A of finite Krull dimension containing the field of rational numbers, an Abelian group called the Euler class group is defined. An element of this group is attached to a projective A-module of rank = dim A and it is shown that the vanishing of this element is necessary and sufficient for P to split off a free summand of rank 1. As one of the applications of this result, it is shown that for any n-dimensional real affine domain, a projective module of rank n (with trivial determinant), all of whose generic sections have n generated vanishing ideals, necessarily splits off a free direct summand of rank 1.     

Noetherian rings with almost injective simple modules

We characterize right Noetherian rings over which all simple modules are almost injective. It is proved that R is such a ring, if and only if, the complements of semisimple submodules of every R-module M are direct summands of M, if and only if, R is a finite direct sum of right ideals I_r, where I_r is either a Noetherian V-module with zero socle, or a simple module, or an injective module of length 2. A commutative Noetherian ring for which all simple modules are almost injective is precisely a finite direct product of rings R_i, where R_i is either a field or a quasi-Frobenius ring of length 2. We show that for commutative rings whose all simple modules are almost injective, the properties of Kasch, (semi)perfect, semilocal, quasi-Frobenius, Artinian, and Noetherian coincide.     

Artinian Serial Modules over Commutative (or,Left Noetherian) Rings are at Most One Step Away from Being Noetherian

We introduce and study the concept of dual perfect dimension which is a Krull-like dimension extension of the concept of acc on finitely generated submodules. We observe some basic facts for modules with this dimension, which are similar to the basic properties of modules with Noetherian dimension. For Artinian serial modules, we show that these two dimensions coincide. Consequently, we prove that the Noetherian dimension of non-Noetherian Artinian serial modules over the rings of the title is 1.