Lemma isirreflapSet {X : apSet} : ∏ x : X, ¬ (x # x). Proof. exact (pr1 (pr2 (pr2 X))). Qed.
Require Import UniMath.Foundations.Propositions. Require Import UniMath.MoreFoundations.Sets. Require Import UniMath.MoreFoundations.Tactics. Require Import UniMath.MoreFoundations.DecidablePropositions.