theorem
  (A |^ (1, n))? = A |^ (0, n)
proof
  thus (A |^ (1, n))? = {<%>E} \/ (A |^ (1, n)) by Th76
    .= A |^ (0, 0) \/ (A |^ (0 + 1, n)) by Th45
    .= A |^ (0, n) by Th25;
end;
