proposition: Lemma postcompWithCoproductArrow {a : I -> C} (CCab : Coproduct a) {c : C} (f : ∏ i, a i --> c) {x : C} (k : c --> x) : CoproductArrow CCab f · k = CoproductArrow CCab (λ i, f i · k).
proof: Proof. apply CoproductArrowUnique; intro i. now rewrite assoc, CoproductInCommutes. Qed.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.Core.Univalence UniMath.CategoryTheory.FunctorCategory UniMath.CategoryTheory.ProductCategory UniMath.CategoryTheory.Limits.Graphs.Colimits UniMath.CategoryTheory.whiskering