reserve E, x, y, X for set;
reserve A, B, C for Subset of E^omega;
reserve a, b for Element of E^omega;
reserve i, k, l, kl, m, n, mn for Nat;

theorem
  (A |^ (m, n))? c= A*
proof
  (A |^ (m, n))? = (A |^ (m, n)) |^ (0, 1) by Th79;
  hence thesis by Th71;
end;
