Section Comp.
Context {K : AbsRing} {V : NormedModule K}.
End Comp.
(** * Mean value theorem *)

Lemma incr_function (f : R -> R) (a b : Rbar) (df : R -> R) :
(forall (x : R), Rbar_lt a x -> Rbar_lt x b -> is_derive f x (df x))
-> ((forall (x : R), Rbar_lt a x -> Rbar_lt x b -> df x > 0)
-> (forall (x y : R), Rbar_lt a x -> x < y -> Rbar_lt y b -> f x < f y)).