Definition sum_of_functor_inl {Q C₁ C₂ : category} (F : C₁ ⟶ Q) (G : C₂ ⟶ Q) : inl_functor C₁ C₂ ∙ sum_of_functors F G ⟹ F. Proof. use make_nat_trans. - exact (λ z, identity _). - abstract (intros x₁ x₂ f ; cbn ; rewrite id_left, id_right ; apply idpath). Defined.
Require Import UniMath.Foundations.All. Require Import UniMath.MoreFoundations.All. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Functors. Require Import UniMath.CategoryTheory.Core.NaturalTransformations. Require Import UniMath.CategoryTheory.Core.Isos. Require Import UniMath.CategoryTheory.Core.Univalence. Require Import UniMath.CategoryTheory.whiskering.