proposition: Lemma Feq_imp_eq : Feq I F G -> forall x, I x -> forall Hx Hx', F x Hx [=] G x Hx'.
proof: Proof. intros H x Hx1 Hx Hx'. elim H; intros H0 H1. elim H1; auto. Qed.
imports: CoRN.reals.Intervals CoRN.tactics.DiffTactics1