theorem
  (1_G) |^ i = 1_G
proof
  (1_G) |^ i = (1_G) |^ |.i.| or
    (1_G) |^ i = ((1_G) |^ |.i.|)" & (1_G)" = 1_G by Def8,Th8;
  hence thesis by Lm4;
end;
