满足(accr)环的I-adic完备化及其平坦性

满足（ａｃｃｒ）环是比Ｎｏｅｔｈｅｒ环更广泛的一类环，本文讨论了满足（ａｃｃｒ）环的Ｉ－ａｄｉｃ完备化及其平坦性问题，把Ｎｏｅｔｈｅｒ环的有关结果推广到满足（ａｃｃｒ）环上，同时也改进了［１］中的结果．     

Representations of q-analogue of the Virasoro Algebra

Ｒｅｐｒｅｓｅｎｔａｔｉｏｎｓｏｆｑ┐ａｎａｌｏｇｕｅｏｆｔｈｅＶｉｒａｓｏｒｏＡｌｇｅｂｒａ＊）ＺｈａｏＫａｉｍｉｎｇ（赵开明）（ＤｅｐａｒｔｍｅｎｔｏｆＰｕｒｅＭａｔｈ．，ＵｎｉｖｅｒｓｉｔｙｏｆＷａｔｅｒｌｏｏ，Ｗａｔｅｒｌｏｏ，Ｏｎｔａｒｉｏ...     

Absolutely Pure Covers

Absolutely pure modules act in ways similar to injective modules. There are conditions on a ring which guarantee that the class of injective modules will be covering. In this article, we define conditions on the ring R which guarantee that the class of absolutely pure modules will be covering. These include R being left coherent, which we show implies a number of other necessary properties.     

Exchange环的比较结构

本文得到了相关比较Exchange环上模的替代性,并研究了幂比较Exchange 环上模的结构,进而提供了一类新的相关比较:Exchange环.     

The Comparable Structure of Exchange Rings

We obtain a new substitution for modules over exchange rings satisfying related comparability. Also we investigate the structure of modules over exchange rings satisfying power comparability and provide a new class of exchange rings satisfying related comparability. Received June 1, 1998, Revised November 15, 1999, Accepted June 1, 2000     

Modules Characterized by Injectivity Clases

ＭｏｄｕｌｅｓＣｈａｒａｃｔｅｒｉｚｅｄｂｙＩｎｊｅｃｔｉｖｉｔｙＣｌａｓｅｓＷａｎｇＤｉｎｇｇｕｏ（王顶国）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＱｕｆｕＮｏｒｍａｌＵｎｉｖｅｒｓｉｔｙ，Ｑｕｆｕ，Ｓｈａｎｄｏｎｇ，２７３１６５）Ａｂｓ...     

Canonical Tilting Modules Over Shod Algebras are Regular in Codimension One

We show that for a class of modules over shod algebras, including the canonical tilting modules, the closures of the corresponding orbits in module varieties are regular in codimension one.     

相关Hopf模的对偶

本文的目的就是给出相关Hopf模的对偶性质.在第一部分,证明了相关Hopf模的对偶模仍是相关Hopf模.特别地,Hopf模的对偶仍是Hopf模.在第二、第三两部分,分别给出相关Hopf模的对偶相关Hopf模的基本结构定理及Maschke定理.     

Loewy Modules with Finite Loewy Invariants and Max Modules with Finite Radical Invariants

Over a commutative ring R, a module is artinian if and only if it is a Loewy module with finite Loewy invariants [5 Facchini , A. ( 1981 ). Loewy and artinian modules over commutative rings . Ann. Mat. Pura Appl. 128 : 359 – 374 .[Crossref], [Web of Science ®] , [Google Scholar]]. In this paper, we show that this is not necesarily true for modules over noncommutative rings R, though every artinian module is always a Loewy module with finite Loewy invariants. We prove that every Loewy module with finite Loewy invariants has a semilocal endomorphism ring, thus generalizing a result proved by Camps and Dicks for artinian modules [3 Camps , R. , Dicks , W. ( 1993 ). On semilocal rings . Israel J. Math. 81 : 203 – 211 .[Crossref], [Web of Science ®] , [Google Scholar]]. Finally, we obtain similar results for the dual class of max modules.     

Length two extensions of modules for the Witt algebra

In this paper, we establish an explicit classification of length two extensions of tensor modules for the Witt algebra using the cohomology of the Witt algebra with coe?cients in the module of the space of homomorphisms between the two modules of interest. To do this we extended our module to a module that has a compatible action of the commutative algebra of Laurent polynomials in one variable. In this setting, we are be able to directly compute all possible 1-cocycles.     

模的弱消去问题与qu－正则环

本文考虑模的弱消去问题与正则环的Ｓｔａｂｌｅｒａｎｇｅ条件，引进了ｑｕ－正则环的概念，并用它刻划了一类满足弱消去条件的模，刻划了ｑｕ－正则环，指出一切满足比较公理的正则环均为ｑｕ－正则环．文中还考虑这些结果的应用．例如，刻划了满足弱消去律的拟内射模；证明了素的正则右自内射环上的任意非奇异内射右Ｒ－模可以从直和项中弱消去．     

On a Conjecture of Groves for Modules Over Infinite Nilpotent Groups

We show that a conjecture of Groves for modules over nilpotent groups of class 2 holds for the codimension 2 case with certain assumptions.     

模的弱消去问题与qu－正则环

本文考虑模的弱消去问题与正则环的Ｓｔａｂｌｅｒａｎｇｅ条件，引进了ｑｕ－正则环的概念，并用它刻划了一类满足弱消去条件的模，刻划了ｑｕ－正则环，指出一切满足比较公理的正则环均为ｑｕ－正则环．文中还考虑这些结果的应用．例如，刻划了满足弱消去律的拟内射模；证明了素的正则右自内射环上的任意非奇异内射右Ｒ－模可以从直和项中弱消去．     

A characterization of selfinjective algebras of strictly canonical type

We prove that the class of selfinjective algebras of strictly canonical type, investigated in Kwiecień and Skowroński (2009) [27], Kwiecień and Skowroński (2009) [28], coincides with the class of selfinjective algebras having triangular Galois coverings with infinite cyclic group and the Auslander–Reiten quiver with quasi-tubes maximally saturated by simple and projective modules, satisfying natural conditions.     

Representations of a Noncommutative Associative Algebra Related to Quantum Torus of Rank Three

In this paper, we present some modules over the rank-three quantized Weyl algebra, which are closely related to modules over some vertex algebras. The isomorphism classes among these modules are also determined.     

On Graded Distributive Modules

ＯｎＧｒａｄｅｄＤｉｓｔｒｉｂｕｔｉｖｅＭｏｄｕｌｅｓ￥ＣｈｅｎＱｉｎｇｈｕａ（陈清华）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＦｕｊｉａｎＮｏｒｍａｌＵｎｉｖｅｒｓｉｔｙ，Ｆｕｚｈｏｕ，３５０００７）Ａｂｓｔｒａｃｔ：Ｉｎｔｈｉｓｐａｐｅ...     

Some Classes of Nilpotent Associative Algebras

We further the study of rings with no middle class by focusing on an interpretation of that property in terms of the lattice of hereditary pretorsion classes over a given ring. For non-semisimple rings, the absence of a middle class is equivalent to the requirement that the class of all semisimple right modules be a coatom in that lattice. Taking advantage of this perspective, we discover new facts and shed light on others already known with a possibly more direct interpretation without having to refer to an exhaustive analysis of the structure theorems available in the literature. Our approach also allows us to characterize rings with no middle class in terms of hereditary pretorsion classes containing the class of all singular right modules. We discuss the open problem of whether there is a ring with no right middle class which is not right Noetherian and see, in particular, that an indecomposable ring satisfying that property would have to be Morita equivalent to a certain type of subring of a full linear ring.     

On Regular Rings Satisfying Almost Comparability

In this article, we study regular rings satisfying almost comparability. We first show that, for regular rings, almost comparability is inherited by finitely generated projective modules and finite matrix rings, and, as a main result, we prove that the strict cancellation property holds for the family of all finitely generated projective modules over directly finite regular rings satisfying almost comparability.