Definition RInt (f : R -> V) (a b : R) := iota (is_RInt f a b).

Lemma RInt_le (f g : R -> R) (a b : R) : a <= b -> ex_RInt f a b -> ex_RInt g a b-> (forall x, a < x < b -> f x <= g x) -> RInt f a b <= RInt g a b.