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 Th98:
  m <= n implies A? |^ (m, n) = A |^ (0, n)
proof
  assume m <= n;
  hence A? |^ (m, n) = A? |^ (0, n) by Th96
    .= A |^ (0, n) by Th97;
end;
