theorem
  A+ = A |^ (1, n) \/ A |^.. (n + 1)
proof
A1: 0 + 1 <= n + 1 by XREAL_1:7;
  thus A+ = A |^.. 1 by Th50
    .= A |^ (1, n) \/ A |^.. (n + 1) by A1,Th7;
end;
