proposition: Lemma iscotranstightapSet {X : tightapSet} : ∏ x y z : X, x ≠ z -> x ≠ y ∨ y ≠ z.
proof: Proof. exact iscotransapSet. Qed.
imports: UniMath.Algebra.BinaryOperations UniMath.Foundations.Propositions UniMath.MoreFoundations.Sets UniMath.MoreFoundations.Tactics UniMath.MoreFoundations.DecidablePropositions