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One-sided Gorenstein subcategories

Weiling Song, Tiwei Zhao, Zhaoyong Huang (2020)

Czechoslovak Mathematical Journal

We introduce the right (left) Gorenstein subcategory relative to an additive subcategory 𝒞 of an abelian category 𝒜 , and prove that the right Gorenstein subcategory r 𝒢 ( 𝒞 ) is closed under extensions, kernels of epimorphisms, direct summands and finite direct sums. When 𝒞 is self-orthogonal, we give a characterization for objects in r 𝒢 ( 𝒞 ) , and prove that any object in 𝒜 with finite r 𝒢 ( 𝒞 ) -projective dimension is isomorphic to a kernel (or a cokernel) of a morphism from an object in 𝒜 with finite 𝒞 -projective dimension...

Realization of long exact sequences of abelian groups.

Irwin S. Pressman (1990)

Publicacions Matemàtiques

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...

Sobre resolubilidad en una categoría de Burgin.

Leoncio Franco Fernández (1979)

Revista Matemática Hispanoamericana

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...

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