English
The coimage projection composed with the Abelian factor through coimage equals f; i.e., coimage.π f ≫ Abelian.factorThruCoimage f = f.
Русский
Проекция кообраза в композиции с через кообразовую факторизацию равна f; то есть coimage.π f ≫ Abelian.factorThruCoimage f = f.
LaTeX
$$$\mathrm{coimage.\pi}(f) \circ \mathrm{Abelian.factorThruCoimage}(f) = f$$$
Lean4
/-- `f` factors through its coimage via the canonical morphism `p`. -/
protected theorem fac : coimage.π f ≫ Abelian.factorThruCoimage f = f :=
cokernel.π_desc _ _ _