proposition: Proposition comp_functor_runitor {C₁ C₂ C₃ : category} {D₁ : twosided_disp_cat C₁ C₁} {D₂ : twosided_disp_cat C₂ C₂} {D₃ : twosided_disp_cat C₃ C₃} {I₁ : hor_id D₁} {I₂ : hor_id D₂} {I₃ : hor_id D₃} {Cm₁ : hor_comp D₁} {Cm₂ : hor_comp D₂} {Cm₃ : hor_comp D₃} {r₁ : double_cat_runitor I₁ Cm₁} {r₂ : double_cat_runitor I₂ Cm₂} {r₃ : double_cat_runitor I₃ Cm₃} {F : C₁ ⟶ C₂} {FF : twosided_disp_functor F F D₁ D₂} {G : C₂ ⟶ C₃} {GG : twosided_disp_functor G G D₂ D₃} {FI : double_functor_hor_id FF I₁ I₂} {GI : double_functor_hor_id GG I₂ I₃} {FC : double_functor_hor_comp FF Cm₁ Cm₂} {GC : double_functor_hor_comp GG Cm₂ Cm₃} (Fl : double_functor_runitor r₁ r₂ FI FC) (Gl : double_functor_runitor r₂ r₃ GI GC) : double_functor_runitor r₁ r₃ (comp_hor_id FI GI) (comp_hor_comp FC GC).
proof: Proof. intros x y f ; cbn. rewrite two_disp_post_whisker_b. rewrite two_disp_pre_whisker_b. unfold transportb_disp_mor2. rewrite transport_f_f_disp_mor2. rewrite Gl, Fl. rewrite transportf_twosided_disp_functor. rewrite two_disp_post_whisker_f. rewrite transport_f_f_disp_mor2. rewrite twosided_disp_functor_comp. rewrite two_disp_post_whisker_b. unfold transportb_disp_mor2. rewrite transport_f_f_disp_mor2. rewrite twosided_disp_functor_comp. rewrite two_disp_pre_whisker_b. rewrite two_disp_post_whisker_b. unfold transportb_disp_mor2. rewrite transport_f_f_disp_mor2. rewrite assoc_two_disp_alt. rewrite transport_f_f_disp_mor2. etrans. { do 2 apply maponpaths. rewrite assoc_two_disp. apply idpath. } rewrite two_disp_post_whisker_b. unfold transportb_disp_mor2. rewrite transport_f_f_disp_mor2. etrans. { do 2 apply maponpaths. apply maponpaths_2. rewrite assoc_two_disp. rewrite functor_double_comp_eq_alt. unfold transportb_disp_mor2. rewrite two_disp_pre_whisker_f. rewrite transport_f_f_disp_mor2. apply idpath. } rewrite two_disp_pre_whisker_f. rewrite two_disp_post_whisker_f. rewrite transport_f_f_disp_mor2. rewrite assoc_two_disp. unfold transportb_disp_mor2. rewrite transport_f_f_disp_mor2. rewrite assoc_two_disp. unfold transportb_disp_mor2. rewrite two_disp_pre_whisker_f. rewrite transport_f_f_disp_mor2. rewrite assoc_two_disp. unfold transportb_disp_mor2. rewrite two_disp_pre_whisker_f. rewrite two_disp_pre_whisker_f. rewrite transport_f_f_disp_mor2. rewrite <- double_hor_comp_mor_comp. rewrite id_two_disp_left. rewrite twosided_disp_functor_id. unfold transportb_disp_mor2. rewrite transport_f_f_disp_mor2. refine (!_). etrans. { rewrite assoc_two_disp. unfold transportb_disp_mor2. rewrite two_disp_pre_whisker_f. rewrite transport_f_f_disp_mor2. apply idpath. } etrans. { apply maponpaths. do 3 apply maponpaths_2. apply (double_hor_comp_mor_transportf_disp_mor2_right _ (!(id_left _ @ functor_id _ _))). } rewrite !two_disp_pre_whisker_f. rewrite transport_f_f_disp_mor2. use transportf_disp_mor2_eq. do 4 apply maponpaths_2. use transportf_disp_mor2_eq. apply idpath. Qed.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.TwoSidedDisplayedCats.TwoSidedDispCat UniMath.CategoryTheory.TwoSidedDisplayedCats.Isos UniMath.CategoryTheory.TwoSidedDisplayedCats.DisplayedFunctor UniMath.Bicategories.DoubleCategories.Basics.DoubleCategoryBasics UniMath.Bicategories.DoubleCategories.Core.DoubleFunctor.Basics