proposition: Proposition double_hor_comp_mor_id {C : category} {D : twosided_disp_cat C C} (Cm : hor_comp D) {x y z : C} (h₁ : D x y) (h₂ : D y z) : double_hor_comp_mor Cm (id_two_disp h₁) (id_two_disp h₂) = id_two_disp (double_hor_comp Cm h₁ h₂).
proof: Proof. exact (pr12 Cm x y z h₁ h₂). Defined.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.TwoSidedDisplayedCats.TwoSidedDispCat UniMath.CategoryTheory.TwoSidedDisplayedCats.Isos