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

Lemma abs_RInt_le_const : forall (f : R -> R) a b M, a <= b -> ex_RInt f a b -> (forall t, a <= t <= b -> Rabs (f t) <= M) -> Rabs (RInt f a b) <= (b - a) * M.