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? ^^ (A*) = A* ^^ (A?)
proof
  thus A? ^^ (A*) = A |^ (0, 1) ^^ (A*) by Th79
    .= A* ^^ (A |^ (0, 1)) by Th66
    .= A* ^^ (A?) by Th79;
end;
