It is a standard result of elementary homological algebra that to every R-module $A$ there exists a projective resolution. It is often said that the category of R-modules has "enough proje tives.projectives." In which other categories is this also true? In particular is it true for abelian categories?
It is a standard result of elementary homological algebra that to every R-module $A$ there exists a projective resolution. It is often said that the category of R-modules has "enough proje tives." In which other categories is this also true? In particular is it true for abelian categories?