fact: Definition is_z_isomorphism {C : precategory_data} {a b : ob C} (f : a --> b) := ∑ g, is_inverse_in_precat f g.
imports: UniMath.Foundations.PartA UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.MoreFoundations.Tactics UniMath.CategoryTheory.Core.Categories