reserve
  a,b,c,d,e for Ordinal,
  m,n for Nat,
  f for Ordinal-Sequence,
  x for object;
reserve S,S1,S2 for Sequence;

theorem Th16:
  a |^|^ 1 = a
  proof
    0+1 = succ 0;
    hence a |^|^ 1 = exp(a, a|^|^0) by Th14 .= exp(a, 1) by Th13
       .= a by ORDINAL2:46;
  end;
