-radicals and -radicals in the category of modules.
TAG-modules with complement submodules -pure.
Tame algebras with strongly simply connected Galois coverings
Tauvel's height formula in iterated differential operator rings.
Ternary algebras and calculus of cubic matrices
We study associative ternary algebras and describe a general approach which allows us to construct various classes of ternary algebras. Applying this approach to a central bimodule with a covariant derivative we construct a ternary algebra whose ternary multiplication is closely related to the curvature of the covariant derivative. We also apply our approach to a bimodule over two associative (binary) algebras in order to construct a ternary algebra which we use to produce a large class of Lie algebras....
The almost isomorphism relation for simple regular rings.
A longstanding open problem in the theory of von Neumann regular rings is the question of whether every directly finite simple regular ring must be unit-regular. Recent work on this problem has been done by P. Menal, K. C. O'Meara, and the authors. To clarify some aspects of these new developments, we introduce and study the notion of almost isomorphism between finitely generated projective modules over a simple regular ring.
The Armendariz module and its application to the Ikeda-Nakayama module.
The Auslander generators of the exterior algebra in two variables
We compute a complete set of nonisomorphic minimal Auslander generators for the exterior algebra in two variables.
The canonical algebras
The category of groupoid graded modules
We introduce the abelian category R-gr of groupoid graded modules and give an answer to the following general question: If U: R-gr → R-mod denotes the functor which associates to any graded left R-module M the underlying ungraded structure U(M), when does either of the following two implications hold: (I) M has property X ⇒ U(M) has property X; (II) U(M) has property X ⇒ M has property X? We treat the cases when X is one of the properties: direct summand, free, finitely generated, finitely presented,...
The category of modules with good filtrations over a quasi-hereditary algebra has almost split sequences.
The Chu construction.
The closure of radical classes under finite subdirect products
The component quiver of a self-injective artin algebra
We prove that the component quiver of a connected self-injective artin algebra A of infinite representation type is fully cyclic, that is, every finite set of components of the Auslander-Reiten quiver of A lies on a common oriented cycle in .
The construction of -solvable Abelian groups
The Construction of Almost Split Sequences, III: Modules Over Two Classes of Tame Local Algebras.
The converse of Schur's Lemma in group rings
In this paper, we study the structure of group rings by means of endomorphism rings of their modules. The main tools used here, are the subrings fixed by automorphisms and the converse of Schur's lemma. Some results are obtained on fixed subrings and on primary decomposition of group rings.
The derived functors of and protorsion modules
The existence of envelopes
The existence of relative pure injective envelopes
Let 𝓢 be a class of finitely presented R-modules such that R∈ 𝓢 and 𝓢 has a subset 𝓢* with the property that for any U∈ 𝓢 there is a U*∈ 𝓢* with U* ≅ U. We show that the class of 𝓢-pure injective R-modules is preenveloping. As an application, we deduce that the left global 𝓢-pure projective dimension of R is equal to its left global 𝓢-pure injective dimension. As our main result, we prove that, in fact, the class of 𝓢-pure injective R-modules is enveloping.