Some decomposition properties of injective and pure-injective modules

JL Garcia, NV Dung - 1994 - projecteuclid.org
It is well known that over a left Notherian ring any direct sum of injecive modules is again
injective, and every injective module is a direct sum of indecomposable modules. Faith [6] …

[PDF][PDF] Exactly definable categories

H Krause - Journal of Algebra, 1998 - Citeseer
Mod ª Ex C, Ab, M¬ Hom y, M my Ž. Ž. Ž. is an equivalence. Thus we can replace a-module
by an exact functor Ž. op C ª Ab. Of course, since the work of Auslander, it has been common …

Modules with cosupport and injective functors

H Holm - Algebras and Representation Theory, 2010 - Springer
Several authors have studied the filtered colimit closure \varinjlimB of a class B of finitely
presented modules. Lenzing called \varinjlimB the category of modules with support in B …

Auslander's formula for contravariantly finite subcategories

J Asadollahi, R Hafezi, MH Keshavarz - Journal of the Mathematical …, 2021 - jstage.jst.go.jp
Let A be a right coherent ring and X be a contravariantly finite subcategory of mod-A
containing projectives. In this paper, we construct a recollement of abelian categories (mod0 …

Torsion and torsion-free classes from objects of finite type in Grothendieck categories

D Bravo, S Odabaşı, CE Parra, MA Pérez - Journal of Algebra, 2022 - Elsevier
In an arbitrary Grothendieck category, we find necessary and sufficient conditions for the
class of FP n-injective objects to be a torsion class. By doing so, we propose a notion of n …

Extensions, kernels and cokernels of homologically finite subcategories

R Gentle, G Todorov - Representation theory of algebras …, 1996 - books.google.com
We prove the following results for the subcategories of an abelian category: 1) The full
subcategory whose objects are kernels of the maps between two covariantly finite …

A functorial approach to modules of G-dimension zero

Y Yoshino - Illinois Journal of Mathematics, 2005 - projecteuclid.org
Let R be a commutative Noetherian ring and let G be the category of modules of G-
dimension zero over R. We denote the associated stable category by G. We show that the …

Adjoint functors and equivalences of subcategories

FC Iglesias, J Gómez-Torrecillas, R Wisbauer - Bulletin des sciences …, 2003 - Elsevier
For any left R-module P with endomorphism ring S, the adjoint pair of functors P⊗ S− and
HomR (P,−) induce an equivalence between the categories of P-static R-modules and P …

Covers, precovers, and purity

H Holm, P Jørgensen - Illinois Journal of Mathematics, 2008 - projecteuclid.org
We show that if a class of modules is closed under pure quotients, then it is precovering if
and only if it is covering, and this happens if and only if it is closed under direct sums. This is …

[引用][C] Purity through Gabriel's functor rings

JL Garcıa, JM Hernández - Bull. Soc. Math. Belgique, 1993