proposition: Lemma interval_Max: forall {a b : IR} {I : interval}, I a -> I b -> I (Max a b).
proof: Proof. intros ? ? ? Ha Hb. destruct I; simpl in Ha, Hb; simpl; try (split; destruct Ha, Hb); eauto using less_leEq_trans, leEq_reflexive, leEq_transitive, lft_leEq_Max, Max_less, Max_leEq. Qed.
imports: CoRN.ftc.NthDerivative