theorem
  |(<e2>,<e2>)| = 1
proof
  <e2>.1 = 0 & <e2>.2 = 1 & <e2>.3 = 0;
  then |(<e2>,<e2>)| = 0 * 0 + 1 * 1 + 0 * 0 by Lm5
  .= 1;
  hence thesis;
end;
