mathlib

2689c517 - feat(category_theory/abelian): abelian categories with enough projectives have projective resolutions (#7488)

feat(category_theory/abelian): abelian categories with enough projectives have projective resolutions (#7488) Co-authored-by: Scott Morrison <scott.morrison@gmail.com> Co-authored-by: Johan Commelin <johan@commelin.net>