On Multiplicative Bases in Quasi Frobenius Algebras.
First, we give a complete description of the indecomposable prime modules over a Dedekind domain. Second, if is the pullback, in the sense of [9], of two local Dedekind domains then we classify indecomposable prime -modules and establish a connection between the prime modules and the pure-injective modules (also representable modules) over such rings.
A class of semirings, so called p-semirings, characterized by a natural number p is introduced and basic properties are investigated. It is proved that every p-semiring is a union of skew rings. It is proved that for some p-semirings with non-commutative operations, this union contains rings which are commutative and possess an identity.
Let be a ring. A right -module is said to be retractable if whenever is a non-zero submodule of . The goal of this article is to investigate a ring for which every right R-module is retractable. Such a ring will be called right mod-retractable. We proved that The ring is right mod-retractable if and only if each is a right mod-retractable ring for each , where is an arbitrary finite set. If is a mod-retractable ring then is a mod-retractable ring.
This paper is motivated by the question whether there is a nice structure theory of finitely generated modules over the Iwasawa algebra, i.e. the completed group algebra, of a -adic analytic group . For without any -torsion element we prove that is an Auslander regular ring. This result enables us to give a good definition of the notion of a pseudo-null -module. This is classical when for some integer , but was previously unknown in the non-commutative case. Then the category of -modules...
The purpose of this paper is to further the study of weakly injective and weakly projective modules as a generalization of injective and projective modules. For a locally q.f.d. module , there exists a module such that is weakly injective in , for any . Similarly, if is projective and right perfect in , then there exists a module such that is weakly projective in , for any . Consequently, over a right perfect ring every module is a direct summand of a weakly projective module. For...