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