Definition comp_h_square {C : double_cat} {x₁ x₂ y₁ y₂ z₁ z₂ : C} {v₁ : x₁ -->v x₂} {v₂ : y₁ -->v y₂} {v₃ : z₁ -->v z₂} {h₁ : x₁ -->h y₁} {h₂ : y₁ -->h z₁} {k₁ : x₂ -->h y₂} {k₂ : y₂ -->h z₂} (s₁ : square v₁ v₂ h₁ k₁) (s₂ : square v₂ v₃ h₂ k₂) : square v₁ v₃ (h₁ ·h h₂) (k₁ ·h k₂) := double_hor_comp_mor (hor_comp_double_cat C) s₁ s₂.
Require Import UniMath.MoreFoundations.All. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Functors. Require Import UniMath.CategoryTheory.Core.NaturalTransformations. Require Import UniMath.CategoryTheory.Core.Isos. Require Import UniMath.CategoryTheory.TwoSidedDisplayedCats.TwoSidedDispCat. Require Import UniMath.CategoryTheory.TwoSidedDisplayedCats.Isos. Require Import UniMath.CategoryTheory.TwoSidedDisplayedCats.Univalence. Require Import UniMath.Bicategories.Core.Examples.BicatOfUnivCats. Require Import UniMath.Bicategories.DoubleCategories.Basics.DoubleCategoryBasics.