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On some classes of modules

Gonca Güngöroglu, Harmanci, Abdullah (2000)

Czechoslovak Mathematical Journal

The aim of this paper is to investigate quasi-corational, comonoform, copolyform and α -(co)atomic modules. It is proved that for an ordinal α a right R -module M is α -atomic if and only if it is α -coatomic. And it is also shown that an α -atomic module M is quasi-projective if and only if M is quasi-corationally complete. Some other results are developed.

On some Results Related to Köthe's Conjecture

Agata, Smoktunowicz (2001)

Serdica Mathematical Journal

The Köthe conjecture states that if a ring R has no nonzero nil ideals then R has no nonzero nil one-sided ideals. Although for more than 70 years significant progress has been made, it is still open in general. In this paper we survey some results related to the Köthe conjecture as well as some equivalent problems.

On split-by-nilpotent extensions

Ibrahim Assem, Dan Zacharia (2003)

Colloquium Mathematicae

Let A and R be two artin algebras such that R is a split extension of A by a nilpotent ideal. We prove that if R is quasi-tilted, or tame and tilted, then so is A. Moreover, generalizations of these properties, such as laura and shod, are also inherited. We also study the relationship between the tilting R-modules and the tilting A-modules.

On stable equivalences of module subcategories over a semiperfect noetherian ring

Noritsugu Kameyama, Yuko Kimura, Kenji Nishida (2014)

Colloquium Mathematicae

Given a semiperfect two-sided noetherian ring Λ, we study two subcategories k ( Λ ) = M m o d Λ | E x t Λ j ( T r M , Λ ) = 0 ( 1 j k ) and k ( Λ ) = N m o d Λ | E x t Λ j ( N , Λ ) = 0 ( 1 j k ) of the category mod Λ of finitely generated right Λ-modules, where Tr M is Auslander’s transpose of M. In particular, we give another convenient description of the categories k ( Λ ) and k ( Λ ) , and we study category equivalences and stable equivalences between them. Several results proved in [J. Algebra 301 (2006), 748-780] are extended to the case when Λ is a two-sided noetherian semiperfect ring.

On structure space of Γ -semigroups

S. Chattopadhyay, S. Kar (2008)

Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica

In this paper we introduce the notion of the structure space of Γ -semigroups formed by the class of uniformly strongly prime ideals. We also study separation axioms and compactness property in this structure space.

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