(** Subtraction *)

Lemma RiemannInt_minus : forall (f g : R -> R) (a b : R)
(pr_f : Riemann_integrable f a b) (pr_g : Riemann_integrable g a b)
(pr : Riemann_integrable (fun x => f x - g x) a b),
RiemannInt pr = RiemannInt pr_f - RiemannInt pr_g.