Lemma iscotranstightapSet {X : tightapSet} : ∏ x y z : X, x ≠ z → x ≠ y ∨ y ≠ z. Proof. exact iscotransapSet. Qed.
Require Import UniMath.Foundations.Propositions. Require Import UniMath.MoreFoundations.Sets. Require Import UniMath.MoreFoundations.Tactics. Require Import UniMath.MoreFoundations.DecidablePropositions.