Definition predoublecategory_square (C : predoublecategory_hor_cat_ver_precat_data) : UU := ∏ (a b c d : C) (f: a -h-> b) (g: a -v-> c) (h: b -v-> d) (k: c -h-> d), UU.
Require Import UniMath.Foundations.Propositions. Require Import UniMath.Foundations.Sets. Require Import UniMath.MoreFoundations.PartA. Require Import UniMath.MoreFoundations.Notations. Require Import UniMath.CategoryTheory.Core.Prelude. Require Import UniMath.CategoryTheory.TwoSidedDisplayedCats.TwoSidedDispCat. Require Import UniMath.CategoryTheory.TwoSidedDisplayedCats.Univalence.