fact: Definition SF_cut_down (sf : @SF_seq R) (x : R) := let s := seq_cut_down ((SF_h sf,SF_h sf) :: (SF_t sf)) x in mkSF_seq (fst (head (SF_h sf,SF_h sf) s)) (behead s).
imports: Coq(Reals Psatz ssreflect ssrbool) mathcomp(seq) Rcomplements Rbar Lub Hierarchy