English
An additive functor preserves the additive isomorphism between the additive biproduct and the image of a biproduct embedding.
Русский
Аддинитивный функтор сохраняет изоморфизм между аддитивным би-производным и образом вложения би-производного.
LaTeX
$$additiveObjIsoBiproduct_hom_π$$
Lean4
@[reassoc (attr := simp)]
theorem additiveObjIsoBiproduct_hom_π (F : Mat_ C ⥤ D) [Functor.Additive F] (M : Mat_ C) (i : M.ι) :
(additiveObjIsoBiproduct F M).hom ≫ biproduct.π _ i = F.map (M.isoBiproductEmbedding.hom ≫ biproduct.π _ i) :=
by
dsimp [additiveObjIsoBiproduct]
rw [biproduct.lift_π, Category.assoc]
erw [biproduct.lift_π, ← F.map_comp]
simp