A Survey of Covers and Envelopes
EE Enochs, OMG Jenda - 2000 - books.google.com
2. Definitions and Remarks If F is class of objects of a category C, by an F-precover of an
object X of C we mean a morphism: F→ X with FF such that Hom (G, F')→ Hom (G, X) is …
object X of C we mean a morphism: F→ X with FF such that Hom (G, F')→ Hom (G, X) is …