
theorem
  for V being RealUnitarySpace, W1,W2 being Subspace of V holds (0).W1
  is Subspace of W2
proof
  let V be RealUnitarySpace;
  let W1,W2 be Subspace of V;
  (0).W1 = (0).W2 by Th31;
  hence thesis;
end;
