On the Schur Multipliers of Steinberg and Chevalley Groups over Commutative Rings.
On the simplicity of some categories of closure spaces
On the size of categories.
On the Spectral Category of Some Rings.
On the structure of Calabi-Yau categories with a cluster tilting subcategory.
On the structure of halfdiagonal-halfterminal-symmetric categories with diagonal inversions
The category of all binary relations between arbitrary sets turns out to be a certain symmetric monoidal category Rel with an additional structure characterized by a family of diagonal morphisms, a family of terminal morphisms, and a family of diagonal inversions having certain properties. Using this properties in [11] was given a system of axioms which characterizes the abstract concept of a halfdiagonal-halfterminal-symmetric monoidal category with diagonal inversions (hdht∇s-category)....
On the structure of locally finite pure semisimple Grothendieck categories
On the structure of triangulated categories with finitely many indecomposables
We study the problem of classifying triangulated categories with finite-dimensional morphism spaces and finitely many indecomposables over an algebraically closed field . We obtain a new proof of the following result due to Xiao and Zhu: the Auslander-Reiten quiver of such a category is of the form where is a disjoint union of simply-laced Dynkin diagrams and a weakly admissible group of automorphisms of . Then we prove that for ‘most’ groups , the category is standard,i.e.-linearly...
On the Swan Subgroup of Certain Periodic Groups.
On the Whitehead theorem in shape theory II
On three types of simplicial objects
On topological modules and duality
On torsionfree classes which are not precover classes
In the class of all exact torsion theories the torsionfree classes are cover (precover) classes if and only if the classes of torsionfree relatively injective modules or relatively exact modules are cover (precover) classes, and this happens exactly if and only if the torsion theory is of finite type. Using the transfinite induction in the second half of the paper a new construction of a torsionfree relatively injective cover of an arbitrary module with respect to Goldie’s torsion theory of finite...
On triangulated orbit categories.
On two types of complete discrete valuation fields
On Underlying Functors in General and Topological Algebra.
On universality of semigroup varieties
A category is called -determined if every set of non-isomorphic -objects such that their endomorphism monoids are isomorphic has a cardinality less than . A quasivariety is called -universal if the lattice of all subquasivarieties of any quasivariety of finite type is a homomorphic image of a sublattice of the lattice of all subquasivarieties of . We say that a variety is var-relatively alg-universal if there exists a proper subvariety of such that homomorphisms of whose image does...
On von Neumann varieties.
On weak -homotopy equivalences of modules
Si definisce il gruppo di —omotopia di un singolo modulo e si introduce la nozione di equivalenza -omotopica debole. Sotto determinate condizioni per l'anello di base oppure per i moduli considerati, le equivalenze -omotopiche deboli coincidono con le equivalenze -omotopiche (forti).
On weak monomorphisms and weak epimorphisms in the category of pro-groups.
In this paper we characterize weak monomorphisms and weak epimorphisms in the category of pro-groups. Also we define the notion of weakly exact sequence and we study this notion in the category of pro-groups.