proposition: Lemma eq_inv_1: forall n1 n2 a1 a2, In n1 a1 -> In n2 a2 -> n1 = n2 -> In n1 (fst (eq_inv a1 a2)) /\ In n2 (snd (eq_inv a1 a2)).
proof: Proof. intros; cbn. subst n2. split; apply meet_1; auto. Qed.
imports: Coq(ZArith Psatz Bool String List FMaps) Coq(FunctionalExtensionality) CDF(Sequences IMP)