proposition: Proposition isaprop_double_nat_trans_hor_id {C₁ C₂ : category} {D₁ : twosided_disp_cat C₁ C₁} {D₂ : twosided_disp_cat C₂ C₂} {F G : C₁ ⟶ C₂} {FF : twosided_disp_functor F F D₁ D₂} {GG : twosided_disp_functor G G D₁ D₂} {τ : F ⟹ G} (ττ : twosided_disp_nat_trans τ τ FF GG) {I₁ : hor_id D₁} {I₂ : hor_id D₂} (FI : double_functor_hor_id FF I₁ I₂) (GI : double_functor_hor_id GG I₁ I₂) : isaprop (double_nat_trans_hor_id ττ FI GI).
proof: Proof. repeat (use impred ; intro). apply isaset_disp_mor. Qed.
imports: UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.TwoSidedDisplayedCats.TwoSidedDispCat UniMath.CategoryTheory.TwoSidedDisplayedCats.Isos UniMath.CategoryTheory.TwoSidedDisplayedCats.DisplayedFunctor UniMath.CategoryTheory.TwoSidedDisplayedCats.DisplayedNatTrans UniMath.Bicategories.DoubleCategories.Basics.DoubleCategoryBasics UniMath.Bicategories.DoubleCategories.Core.DoubleFunctor