fact: Definition RoofTopMor1 {x y : ob C} {R1 R2 : Roof x y} (T : RoofTop R1 R2) : C⟦T, R1⟧ := dirprod_pr1 (pr2 (pr1 T)).
imports: UniMath.Foundations.PartD UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Functors