Coverings in the representation theory of algebras were introduced for the Auslander–
Reiten quiver of a representation-finite algebra in [Ch. Riedtmann, Algebren …

Injective covers of modules were introduced by Enochs [5] as a categorical dual of an
injective envelope and they have been investigated by many authors. The T-torsionfree …

Mathematics | Free Full-Text | Tilting and Cotilting in Functor Categories Next Article in Journal
Preliminary Results on the Preinduction Cervix Status by Shear Wave Elastography Previous …

The paper is aimed at proving the following: for a triangulated category $\underline {C} $
and $ E\subset\mathrm {Obj}\underline {C} $, there exists a cohomological functor $ F $(with …

We establish equivalent conditions under which every object in an Abelian category has a
monic X-cover and an epic X-envelope respectively, when X is a class of objects closed …

Let R be an associative ring with identity. A right R-module M is called cotorsion if Ext"(F,
M)= 0 for every flat right R-module F. These modules were introduced by Harrison [21] in the …

We prove that, for any n≥ 2, the classes of FP n-injective modules and of FP n-flat modules
are both covering and preenveloping over any ring R. This includes the case of FP∞ …

ABSTRACT A module M is called strongly FP-injective if Ext i (P, M)= 0 for any finitely
presented module P and all i≥ 1.(Pre) envelopes and (pre) covers by strongly FP-injective …