reserve T for non empty RelStr,
  A,B for Subset of T,
  x,x2,y,z for Element of T;

theorem Th1:
  T is filled implies A c= A^f
proof
  assume
A1: T is filled;
  let x be object;
  assume
A2: x in A;
  then reconsider y=x as Element of T;
  y in U_FT y by A1,FIN_TOPO:def 4;
  hence thesis by A2,FIN_TOPO:11;
end;
