On Gruenberg Resolutions for Augmented Algebras.
We introduce the right (left) Gorenstein subcategory relative to an additive subcategory of an abelian category , and prove that the right Gorenstein subcategory is closed under extensions, kernels of epimorphisms, direct summands and finite direct sums. When is self-orthogonal, we give a characterization for objects in , and prove that any object in with finite -projective dimension is isomorphic to a kernel (or a cokernel) of a morphism from an object in with finite -projective dimension...
Given a long exact sequence of abelian groupsL: ... → Li-1 →ξi-1 Li →ξi Li+1 → ...a short exact sequence of complexes of free abelian groups is constructed whose cohomology long exact sequence is precisely L. In this sense, L is realized. Two techniques which are introduced to reduce or replace lengthy diagram chasing arguments may be of interest to some readers. One is an arithmetic of bicartesian squares; the other is the use of the fact that categories of morphisms of abelian categories...
En un trabajo de Huq se introduce el concepto de resolubilidad en categorías [2]. En mi tesis doctoral [1 (4.2.3), p.87] se hace distinción entre resolubilidad fuerte (resolubilidad de Huq) y resolubilidad, conceptos que coinciden en el caso de grupos, anillos asociativos y álgebras de Lie, pero no en cualquier tipo de Ω-grupos, donde la resolubilidad corresponde a la introducida en [1].El objeto de esta nota es dar una caracterización de los objetos resolubles (corolario 6), la cual nos permite...