End prod.
(** * The total function [RInt] *)
Section RInt.
Context {V : CompleteNormedModule R_AbsRing}.
Definition RInt (f : R -> V) (a b : R) := iota (is_RInt f a b).

Lemma opp_RInt_swap :
forall f a b,
ex_RInt f a b ->
opp (RInt f a b) = RInt f b a.