reserve L for Lattice,
  p,q,r for Element of L,
  p9,q9,r9 for Element of L.:,
  x, y for set;
reserve I,J for Ideal of L,
  F for Filter of L;

theorem Th27:
  the carrier of L is Ideal of L
proof
  carr(L) is Filter of L.: by FILTER_0:14;
  hence thesis by Th20;
end;
