Torsion group of y2=x(x2+a)


type 1 : P1(0,0)  for all : Z/2Z

 P1O
P1(0,0)OP1
OP1O

type 2 : a=4, Pn(2,±4)  : Z/4Z

 P1P2P3O
P1(2,-4)P3OP2P1
P2(2,4)OP3P1P2
P3(0,0)P2P1OP3
OP1P2P3O

type 3 : a=-c2, Pn(±c,0) : Z/4Z

 P1P2P3O
P1(c,0)OP3P2P1
P2(-c,0)P3OP1P2
P3(0,0)P2P1OP3
OP1P2P3O

  table of curves (English)  

E-mail : kc2h-msm@asahi-net.or.jp
Hisanori Mishima