Lemma isaset_iso {C : precategory_data} (hs : has_homsets C) (a b : ob C) : isaset (iso a b). Proof. change isaset with (isofhlevel 2). apply isofhleveltotal2. - apply hs. - intro f. apply isasetaprop. apply isaprop_is_iso. Qed.
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.