reserve            x for object,
               X,Y,Z for set,
         i,j,k,l,m,n for Nat,
                 r,s for Real,
                  no for Element of OrderedNAT,
                   A for Subset of [:NAT,NAT:];
reserve X,Y,X1,X2 for non empty set,
          cA1,cB1 for filter_base of X1,
          cA2,cB2 for filter_base of X2,
              cF1 for Filter of X1,
              cF2 for Filter of X2,
             cBa1 for basis of cF1,
             cBa2 for basis of cF2;
reserve T for non empty TopSpace,
        s for Function of [:NAT,NAT:], the carrier of T,
        M for Subset of the carrier of T;
reserve cF3,cF4 for Filter of the carrier of T;

theorem Th56:
  lim_filter(s,Frechet_Filter([:NAT,NAT:])) c=
    lim_filter(s,<. all-square-uparrow.))
  proof
    <. all-square-uparrow .) = <. Frechet_Filter(NAT),Frechet_Filter(NAT).)
      by Th34,CARDFIL2:19,Th35;
    hence thesis by Th37,Th39,Th40;
  end;
