proposition: Theorem lt_diff : forall a b:A, a < b -> a <> b.
proof: Proof. intros a b; case a; case b. - intros a0 a1 H e; injection e; intro e'; case (O1.lt_diff _ _ H e'); discriminate. - discriminate. - discriminate. - intros a0 a1 H H0; injection H0; intro e;case (O2.lt_diff _ _ H e). Qed.
imports: Relations List ZArith