proposition: Lemma ex_RInt_swap : forall (f : R -> V) (a b : R), ex_RInt f a b -> ex_RInt f b a.
proof: Proof. intros f a b. case => If HIf. exists (opp If). now apply is_RInt_swap. Qed.
imports: Coq(Reals Psatz) mathcomp(ssreflect ssrbool ssrfun eqtype seq) Markov Rcomplements Rbar Lub Lim_seq SF_seq Continuity Hierarchy