Lemma isaset_z_iso_disp {C : category} {D : disp_cat C} {x y} (f : z_iso x y) (xx : D x) (yy : D y) : isaset (z_iso_disp f xx yy). Proof. apply isaset_total2. - apply homsets_disp. - intros. apply isasetaprop, isaprop_is_z_iso_disp. Qed.
Require Import UniMath.Foundations.Sets. Require Import UniMath.MoreFoundations.PartA. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Isos. Require Import UniMath.CategoryTheory.Core.Univalence. Require Import UniMath.CategoryTheory.DisplayedCats.Core.