fact: Definition roof_comp {x y z : ob C} (R1 : Roof x y) (R2 : Roof y z) : Roof x z.
imports: UniMath.Foundations.PartD UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Functors