reserve n for Nat;

theorem lem1b:
eval(npoly(Z/2,2),1.(Z/2)) = 0.(Z/2)
proof
Char(Z/2) = 2 by RING_3:def 6;
then A: 2 '*' 1.(Z/2) = 0.(Z/2) by RING_3:def 5;
thus eval(npoly(Z/2,2),1.(Z/2))
   = (1.(Z/2)) |^ 2 + 1.(Z/2) by lem1a
  .= 1.(Z/2) * 1.(Z/2) + 1.(Z/2) by prl4
  .= 0.(Z/2) by A,prl3;
end;
