fact: Definition sum_2cell {a₁ a₂ b₁ b₂ : B} {f₁ f₂ : a₁ --> b₁} {g₁ g₂ : a₂ --> b₂} (α : f₁ ==> f₂) (β : g₁ ==> g₂) : f₁ ⊕₁ g₁ ==> f₂ ⊕₁ g₂ := [[ α ▹ ι₁ , β ▹ ι₂ ]].
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Univalence UniMath.CategoryTheory.Adjunctions.Core UniMath.CategoryTheory.Equivalences.Core UniMath.CategoryTheory.Equivalences.FullyFaithful UniMath.CategoryTheory.PrecategoryBinProduct UniMath.Bicategories.Core.Bicat UniMath.Bicategories.Core.Invertible_2cells UniMath.Bicategories.Core.BicategoryLaws UniMath.Bicategories.Core.Unitors UniMath.Bicategories.Core.Univalence UniMath.Bicategories.Core.AdjointUnique UniMath.Bicategories.Core.Examples.BicatOfUnivCats UniMath.Bicategories.Morphisms.Adjunctions