proposition: Lemma istight_CDRap : ∏ x y : X, ¬ (x ≠ y) -> x = y.
proof: Proof. exact (pr2 (pr2 (pr1 (pr2 X)))). Qed.
imports: UniMath.Algebra.DivisionRig UniMath.Algebra.Domains_and_Fields UniMath.Algebra.Apartness UniMath.MoreFoundations.Tactics