reserve U for Universe;
reserve x for Element of U;
reserve U1,U2 for Universe;

theorem
  not GroupObjects(U) is U-petit
  proof
    assume GroupObjects(U) is U-petit;
    then consider x be Element of U such that
A1: x,GroupObjects(U) are_equipotent;
    GroupObjects(U),U are_equipotent by Th83;
    hence thesis by A1,WELLORD2:15,CLASSES4:30;
  end;
