fact: Definition Riemann_sum (f : R -> V) (ptd : SF_seq) : V := foldr plus zero (pairmap (fun x y => (scal (fst y - fst x) (f (snd y)))) (SF_h ptd,zero) (SF_t ptd)).
imports: Coq(Reals Psatz ssreflect ssrbool) mathcomp(seq) Rcomplements Rbar Lub Hierarchy