fact: Definition pr1_idtoiso_concat {C : category} {x y z : C} (f : x = y) (g : y = z) : pr1 (idtoiso (f @ g)) = pr1 (idtoiso f) · pr1 (idtoiso g).
imports: UniMath.Foundations.PartA UniMath.Foundations.Sets UniMath.MoreFoundations.PartA UniMath.MoreFoundations.Tactics UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos