“…3 ) and, in this case, α(1) 6 and α(2) 6 do not vanish simultaneously. (iii) If d 0 = 0 and d 3 = 0 doing the change x → y, y → x, dt → −dt, d i → −d 3−i for i = 0,1, 2, 3 and c i → c 5−i for i = 0, 1, 2, 3, 4, 5, this case is transformed into (ii.1.1) or (ii.1.2).…”