On the cohomology sequence in a semiabelian category.
On the cyclic homology of ringed spaces and schemes.
On the derived categories of coherent sheaves on some homogeneous spaces.
On the derived category of a finite-dimensional algebra.
On the derived category of sheaves on a manifold.
On the Freyd categories of an additive category.
On the maximal exact structure of an additive category
We prove that every additive category has a unique maximal exact structure in the sense of Quillen.
On the notion of precohomology
On the relation between maximal rigid objects and τ-tilting modules
This note compares τ-tilting modules and maximal rigid objects in the context of 2-Calabi-Yau triangulated categories. Let be a 2-Calabi-Yau triangulated category with suspension functor S. Let R be a maximal rigid object in and let Γ be the endomorphism algebra of R. Let F be the functor . We prove that any τ-tilting module over Γ lifts uniquely to a maximal rigid object in via F, and in turn, that projection from to mod Γ sends the maximal rigid objects which have no direct summands from add...
On the Spectral Category of Some Rings.
On the structure of Calabi-Yau categories with a cluster tilting subcategory.
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 three types of simplicial objects
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.
One-sided -suspended categories
For an integer , we introduce a simultaneous generalization of -exact categories and -angulated categories, referred to as one-sided -suspended categories. Notably, one-sided -angulated categories are specific instances of this structure. We establish a framework for transitioning from these generalized categories to their -angulated counterparts. Additionally, we present a method for constructing -angulated quotient categories from Frobenius -prile categories. Our results unify and extend...
Polytopal linear algebra.
Präradikale und Endomorphismenringe von Moduln.
Precovers and Goldie’s torsion theory
Recently, Rim and Teply , using the notion of -exact modules, found a necessary condition for the existence of -torsionfree covers with respect to a given hereditary torsion theory for the category -mod of all unitary left -modules over an associative ring with identity. Some relations between -torsionfree and -exact covers have been investigated in . The purpose of this note is to show that if is Goldie’s torsion theory and is a precover class, then is a precover class whenever...