proposition: Proposition lunitor_square' {C : double_cat} {x₁ x₂ y₁ y₂ : C} {v₁ : x₁ -->v x₂} {v₂ : y₁ -->v y₂} {h₁ : x₁ -->h y₁} {h₂ : x₂ -->h y₂} (s : square v₁ v₂ h₁ h₂) : transportf_square (id_v_right _ @ !(id_v_left _)) (id_v_right _ @ !(id_v_left _)) ((id_h_square _ ⋆h s) ⋆v lunitor_h h₂) = lunitor_h h₁ ⋆v s.
proof: Proof. rewrite lunitor_square. rewrite transportfb_square. apply idpath. Qed.
imports: UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Prelude UniMath.CategoryTheory.TwoSidedDisplayedCats.TwoSidedDispCat UniMath.CategoryTheory.TwoSidedDisplayedCats.Univalence UniMath.Bicategories.Core.Bicat UniMath.Bicategories.DoubleCategories.Core.DoubleCats UniMath.Bicategories.DoubleCategories.DerivedLaws.TransportLaws UniMath.Bicategories.DoubleCategories.Core.DoubleCats UniMath.Bicategories.DoubleCategories.Core.UnivalentDoubleCats