Abelian category with enough projectives
= Abelian category with enough projectives
An <abelian category> has enough projectives when every object admits an <epimorphism> from a <projective object in a category>. Repeating this on the <kernel in a category> constructs a <projective resolution> of every object. Finite direct sums of projective objects remain projective and give the degreewise split horseshoe construction.