fact: Definition profunctor_square_to_nat_trans {C₁ C₂ : category} {F G : C₁ ⟶ C₂} (τ : profunctor_square G F (id_profunctor C₁) (id_profunctor C₂)) : G ⟹ F.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Prelude UniMath.CategoryTheory.Categories.HSET.All UniMath.CategoryTheory.Categories.HSET.SetCoends UniMath.CategoryTheory.Profunctors.Core UniMath.CategoryTheory.Profunctors.Examples UniMath.CategoryTheory.Profunctors.Transformation