theorem
  lim_filter( #Rseq,<. Frechet_Filter(NAT),Frechet_Filter(NAT).)) is
  non empty implies Rseq is P-convergent & {P-lim Rseq} =
  lim_filter( #Rseq,<. Frechet_Filter(NAT),Frechet_Filter(NAT).))
  by Th61,Th62;
