Type11-20.mws

> read `/Documents and Settings/ibuki/My Documents/ESC/ESC.mpl`;
ESC();
 

`Elliptic Surface Calculator v.1.01. c.1990-2008` (1)
 

> with(algcurves):
 

TypeNo.11 

> qc[11]:=y^2*z^2-x^3*z-x^3*y;
 

`:=`(qc[11], `+`(`*`(`^`(y, 2), `*`(`^`(z, 2))), `-`(`*`(`^`(x, 3), `*`(z))), `-`(`*`(`^`(x, 3), `*`(y))))) (1.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[11]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[11]),x,y);
 

{[[0, 1, 0], 2, 1, 1], [[0, 0, 1], 2, 1, 1]} (1.2)
 

> subs(y=t*(x-z)+z,qc[11]);
 

`+`(`*`(`^`(`+`(`*`(t, `*`(`+`(x, `-`(z)))), z), 2), `*`(`^`(z, 2))), `-`(`*`(`^`(x, 3), `*`(z))), `-`(`*`(`^`(x, 3), `*`(`+`(`*`(t, `*`(`+`(x, `-`(z)))), z))))) (1.3)
 

> Q11:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q11, `+`(`-`(`*`(2, `*`(t, `*`(`+`(t, `-`(1)), `*`(U))))), `*`(`+`(`-`(2), t), `*`(`^`(U, 3))), `*`(`^`(t, 2), `*`(`^`(U, 2))), `-`(`*`(`^`(U, 4), `*`(t))), `*`(`^`(`+`(t, `-`(1)), 2)))) (1.4)
 

> subs(U=1,Q11);
simplify(%);
 

`+`(`-`(`*`(2, `*`(t, `*`(`+`(t, `-`(1)))))), `-`(2), `*`(`^`(t, 2)), `*`(`^`(`+`(t, `-`(1)), 2))) (1.5)
 

-1 (1.5)
 

> Quartic_to_Weierstrass(Q11,[1,I]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(t, `-`(6)), `*`(X, `*`(Y, `*`(Z)))), `*`(`+`(`-`(4), `-`(`*`(6, `*`(t)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(`/`(5, 4), `*`(`*`(`^`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(t, `-`(6)), `*`(X, `*`(Y, `*`(Z)))), `*`(`+`(`-`(4), `-`(`*`(6, `*`(t)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(`/`(5, 4), `*`(`*`(`^`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(t, `-`(6)), `*`(X, `*`(Y, `*`(Z)))), `*`(`+`(`-`(4), `-`(`*`(6, `*`(t)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(`/`(5, 4), `*`(`*`(`^`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(t, `-`(6)), `*`(X, `*`(Y, `*`(Z)))), `*`(`+`(`-`(4), `-`(`*`(6, `*`(t)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(`/`(5, 4), `*`(`*`(`^`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(t, `-`(6)), `*`(X, `*`(Y, `*`(Z)))), `*`(`+`(`-`(4), `-`(`*`(6, `*`(t)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(`/`(5, 4), `*`(`*`(`^`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(t, `-`(6)), `*`(X, `*`(Y, `*`(Z)))), `*`(`+`(`-`(4), `-`(`*`(6, `*`(t)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(`/`(5, 4), `*`(`*`(`^`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(t, `-`(6)), `*`(X, `*`(Y, `*`(Z)))), `*`(`+`(`-`(4), `-`(`*`(6, `*`(t)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(`/`(5, 4), `*`(`*`(`^`(...
(1.6)
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
(1.7)
 

> step5(%[1],{x=X,z=Z,y=Y},{x,y,z});
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), `-`(6), `-`(`*`(3, `*`(t)))), `*`(`^`(X, 2), `*`(Z)))), `*`(48, `*`(`+`(`*`(`^`(t, 2)), `-`(4), `-`(`*`(4, `*`(t)))), `*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), `-`(6), `-`(`*`(3, `*`(t)))), `*`(`^`(X, 2), `*`(Z)))), `*`(48, `*`(`+`(`*`(`^`(t, 2)), `-`(4), `-`(`*`(4, `*`(t)))), `*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), `-`(6), `-`(`*`(3, `*`(t)))), `*`(`^`(X, 2), `*`(Z)))), `*`(48, `*`(`+`(`*`(`^`(t, 2)), `-`(4), `-`(`*`(4, `*`(t)))), `*...
(1.8)
 

> mapfactor(subs({X=4*X,Y=8*Y},%[1])/64,[X,Y]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(`+`(`*`(`^`(t, 2)), `-`(6), `-`(`*`(3, `*`(t)))), `*`(`^`(X, 2), `*`(Z))), `*`(3, `*`(`+`(`*`(`^`(t, 2)), `-`(4), `-`(`*`(4, `*`(t)))), `*`(X, `*`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(`+`(`*`(`^`(t, 2)), `-`(6), `-`(`*`(3, `*`(t)))), `*`(`^`(X, 2), `*`(Z))), `*`(3, `*`(`+`(`*`(`^`(t, 2)), `-`(4), `-`(`*`(4, `*`(t)))), `*`(X, `*`(...
(1.9)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (1.10)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(`*`(`^`(t, 2))), 6, `*`(3, `*`(t))), `*`(`^`(x, 2))), `*`(`+`(`-`(`*`(3, `*`(`^`(t, 2)))), 12, `*`(12, `*`(t))), `*`(x)), `-`(`*`(15, `*`(`^`(t, 2)))),... (1.10)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(`*`(`^`(t, 2))), 6, `*`(3, `*`(t))), `*`(`^`(x, 2))), `*`(`+`(`-`(`*`(3, `*`(`^`(t, 2)))), 12, `*`(12, `*`(t))), `*`(x)), `-`(`*`(15, `*`(`^`(t, 2)))),... (1.11)
 

Discriminant = `+`(`*`(16, `*`(`+`(`*`(20, `*`(`^`(t, 6))), `-`(`*`(171, `*`(`^`(t, 5)))), `*`(387, `*`(`^`(t, 4))), `-`(`*`(864, `*`(`^`(t, 3)))), `*`(1512, `*`(`^`(t, 2))), `-`(`*`(1296, `*`(t))), 4... (1.11)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(256, `*`(`^`(t, 6), `*`(`^`(`+`(6, `*`(`^`(t, 2)), `-`(`*`(6, `*`(t)))), 3)))), `*`(`+`(`*`(20, `*`(`^`(t, 6))), `-`(`*`(171, `*`(`^`(t, 5)))), `*`(387, `*`(`^`(... (1.11)
 

`
` (1.11)
 

This is a rational elliptic surface; Oguiso-Shioda type No.11. (1.11)
 

`
` (1.11)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi(
Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi(
Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi(
Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi(
Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi(
(1.11)
 

`
` (1.11)
 

The rank of the Mordell-Weil group over C is 4. (1.11)
 

` ` (1.11)
 

TypeNo.12 

> qc[12]:=(x^2+y^2)^2-x^2*z^2+y^2*z^2;
 

`:=`(qc[12], `+`(`*`(`^`(`+`(`*`(`^`(x, 2)), `*`(`^`(y, 2))), 2)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))), `*`(`^`(y, 2), `*`(`^`(z, 2))))) (2.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[12]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[12]),x,y);
 

{[[0, 0, 1], 2, 1, 2], [[RootOf(`+`(`*`(`^`(_Z, 2)), 1)), 1, 0], 2, 1, 2]} (2.2)
 

> subs(y=t*(x-z)+z,qc[12]);
 

`+`(`*`(`^`(`+`(`*`(`^`(x, 2)), `*`(`^`(`+`(`*`(t, `*`(`+`(x, `-`(z)))), z), 2))), 2)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))), `*`(`^`(`+`(`*`(t, `*`(`+`(x, `-`(z)))), z), 2), `*`(`^`(z, 2)))) (2.3)
 

> Q12:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q12, `+`(`-`(`*`(2, `*`(t, `*`(`+`(t, `-`(1)), `*`(`+`(`*`(2, `*`(`^`(t, 2))), `-`(`*`(4, `*`(t))), 3), `*`(U)))))), `*`(`^`(`+`(1, `*`(`^`(t, 2))), 2), `*`(`^`(U, 4))), `-`(`*`(4, `*`(t, `*`(`+`...
`:=`(Q12, `+`(`-`(`*`(2, `*`(t, `*`(`+`(t, `-`(1)), `*`(`+`(`*`(2, `*`(`^`(t, 2))), `-`(`*`(4, `*`(t))), 3), `*`(U)))))), `*`(`^`(`+`(1, `*`(`^`(t, 2))), 2), `*`(`^`(U, 4))), `-`(`*`(4, `*`(t, `*`(`+`...
(2.4)
 

> subs(U=1,Q12);
simplify(%);
 

`+`(`-`(`*`(2, `*`(t, `*`(`+`(t, `-`(1)), `*`(`+`(`*`(2, `*`(`^`(t, 2))), `-`(`*`(4, `*`(t))), 3)))))), `*`(`^`(`+`(1, `*`(`^`(t, 2))), 2)), `-`(`*`(4, `*`(t, `*`(`+`(t, `-`(1)), `*`(`+`(1, `*`(`^`(t,...
`+`(`-`(`*`(2, `*`(t, `*`(`+`(t, `-`(1)), `*`(`+`(`*`(2, `*`(`^`(t, 2))), `-`(`*`(4, `*`(t))), 3)))))), `*`(`^`(`+`(1, `*`(`^`(t, 2))), 2)), `-`(`*`(4, `*`(t, `*`(`+`(t, `-`(1)), `*`(`+`(1, `*`(`^`(t,...
(2.5)
 

4 (2.5)
 

> Quartic_to_Weierstrass(Q12,[1,2]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`*`(10, `*`(t)), 6), `*`(X, `*`(Y, `*`(Z)))), `*`(128, `*`(`+`(t, 1), `*`(`+`(1, `*`(`^`(t, 2))), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(2,...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`*`(10, `*`(t)), 6), `*`(X, `*`(Y, `*`(Z)))), `*`(128, `*`(`+`(t, 1), `*`(`+`(1, `*`(`^`(t, 2))), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(2,...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`*`(10, `*`(t)), 6), `*`(X, `*`(Y, `*`(Z)))), `*`(128, `*`(`+`(t, 1), `*`(`+`(1, `*`(`^`(t, 2))), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(2,...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`*`(10, `*`(t)), 6), `*`(X, `*`(Y, `*`(Z)))), `*`(128, `*`(`+`(t, 1), `*`(`+`(1, `*`(`^`(t, 2))), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(2,...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`*`(10, `*`(t)), 6), `*`(X, `*`(Y, `*`(Z)))), `*`(128, `*`(`+`(t, 1), `*`(`+`(1, `*`(`^`(t, 2))), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(2,...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`*`(10, `*`(t)), 6), `*`(X, `*`(Y, `*`(Z)))), `*`(128, `*`(`+`(t, 1), `*`(`+`(1, `*`(`^`(t, 2))), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(2,...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`*`(10, `*`(t)), 6), `*`(X, `*`(Y, `*`(Z)))), `*`(128, `*`(`+`(t, 1), `*`(`+`(1, `*`(`^`(t, 2))), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(2,...
(2.6)
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
(2.7)
 

> step5(%[1],{x=X,z=Z,y=Y},{x,y,z});
 

`+`(`-`(`*`(4, `*`(`+`(`*`(8, `*`(t)), `*`(9, `*`(`^`(t, 2))), 7), `*`(`^`(X, 2), `*`(Z))))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(128, `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(8, `*`(t)), ...
`+`(`-`(`*`(4, `*`(`+`(`*`(8, `*`(t)), `*`(9, `*`(`^`(t, 2))), 7), `*`(`^`(X, 2), `*`(Z))))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(128, `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(8, `*`(t)), ...
`+`(`-`(`*`(4, `*`(`+`(`*`(8, `*`(t)), `*`(9, `*`(`^`(t, 2))), 7), `*`(`^`(X, 2), `*`(Z))))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(128, `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(8, `*`(t)), ...
(2.8)
 

> mapfactor(subs({X=4*X,Y=8*Y},%[1])/64,[X,Y]);
 

`+`(`-`(`*`(`+`(`*`(8, `*`(t)), `*`(9, `*`(`^`(t, 2))), 7), `*`(`^`(X, 2), `*`(Z)))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(8, `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(8, `*`(t)), 1), `*`(`+...
`+`(`-`(`*`(`+`(`*`(8, `*`(t)), `*`(9, `*`(`^`(t, 2))), 7), `*`(`^`(X, 2), `*`(Z)))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(8, `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(8, `*`(t)), 1), `*`(`+...
(2.9)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (2.10)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(8, `*`(t)), `*`(9, `*`(`^`(t, 2))), 7), `*`(`^`(x, 2))), `*`(8, `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(8, `*`(t)), 1), `*`(`+`(1, `*`(`^`(t, 2))), `*`(x))...
`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(8, `*`(t)), `*`(9, `*`(`^`(t, 2))), 7), `*`(`^`(x, 2))), `*`(8, `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(8, `*`(t)), 1), `*`(`+`(1, `*`(`^`(t, 2))), `*`(x))...
(2.10)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(8, `*`(t)), `*`(9, `*`(`^`(t, 2))), 7), `*`(`^`(x, 2))), `*`(8, `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(8, `*`(t)), 1), `*`(`+`(1, `*`(`^`(t, 2))), `*`(x))...
`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(8, `*`(t)), `*`(9, `*`(`^`(t, 2))), 7), `*`(`^`(x, 2))), `*`(8, `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(8, `*`(t)), 1), `*`(`+`(1, `*`(`^`(t, 2))), `*`(x))...
(2.11)
 

Discriminant = `+`(`-`(`*`(512, `*`(`+`(`-`(49), `*`(175, `*`(t)), `-`(`*`(153, `*`(`^`(t, 2)))), `*`(81, `*`(`^`(t, 3)))), `*`(`^`(`+`(1, `*`(`^`(t, 2))), 2), `*`(`^`(`+`(t, `-`(1)), 4))))))) (2.11)
 

`+`(jay, `-`(invariant)) = `+`(`-`(`/`(`*`(8, `*`(`^`(`+`(t, `-`(1)), 2), `*`(`^`(`+`(`*`(3, `*`(t)), `-`(5)), 6)))), `*`(`+`(`-`(49), `*`(175, `*`(t)), `-`(`*`(153, `*`(`^`(t, 2)))), `*`(81, `*`(`^`(... (2.11)
 

`
` (2.11)
 

This is a rational elliptic surface; Oguiso-Shioda type No.12. (2.11)
 

`
` (2.11)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (2.11)
 

`
` (2.11)
 

The rank of the Mordell-Weil group over C is 4. (2.11)
 

` ` (2.11)
 

TypeNo.13 

> QC[1]:=x^4+y^4-z^4;
 

>
 

`:=`(QC[1], `+`(`*`(`^`(x, 4)), `*`(`^`(y, 4)), `-`(`*`(`^`(z, 4))))) (3.1)
 

> mapfactor(subs({z=1,x=U},subs(y=t*x,QC[1])),U);
 

`+`(`*`(`+`(`*`(`^`(t, 4)), 1), `*`(`^`(U, 4))), `-`(1)) (3.2)
 

> Quartic_to_Weierstrass(-%,[0,1]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(4, `*`(`^`(t, 4))), 4), `*`(X, `*`(`^`(Z, 2)))))), {Z = `*`(`^`(U, 3)), X = `+`(`*`(2, `*`(`+`(V, 1), `*`(U)))), Y = `+`(`*`(4, `*`(V))...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(4, `*`(`^`(t, 4))), 4), `*`(X, `*`(`^`(Z, 2)))))), {Z = `*`(`^`(U, 3)), X = `+`(`*`(2, `*`(`+`(V, 1), `*`(U)))), Y = `+`(`*`(4, `*`(V))...
(3.3)
 

> Elliptic_surface(%):
Show_data();
 

`
     The curve you have entered is:` (3.4)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(4, `*`(`^`(t, 4))), 4), `*`(x))) (3.4)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(4, `*`(`^`(t, 4))), 4), `*`(x))) (3.4)
 

Discriminant = `+`(`-`(`*`(4096, `*`(`^`(`+`(`*`(`^`(t, 4)), 1), 3))))) (3.4)
 

`+`(jay, `-`(invariant)) = 1728 (3.4)
 

`
` (3.4)
 

This is a rational elliptic surface; Oguiso-Shioda type No.13. (3.4)
 

`
` (3.4)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (3.4)
 

`
` (3.4)
 

The rank of the Mordell-Weil group over C is 4. (3.4)
 

` ` (3.4)
 

TypeNo.14 

> qc[14]:=(x^2+y^2)^2-x^2*z^2+y^2*z^2;
 

`:=`(qc[14], `+`(`*`(`^`(`+`(`*`(`^`(x, 2)), `*`(`^`(y, 2))), 2)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))), `*`(`^`(y, 2), `*`(`^`(z, 2))))) (4.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[14]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[14]),x,y);
 

{[[0, 0, 1], 2, 1, 2], [[RootOf(`+`(`*`(`^`(_Z, 2)), 1)), 1, 0], 2, 1, 2]} (4.2)
 

> subs(y=t*(x-z),qc[14]);
 

`+`(`*`(`^`(`+`(`*`(`^`(x, 2)), `*`(`^`(t, 2), `*`(`^`(`+`(x, `-`(z)), 2)))), 2)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))), `*`(`^`(t, 2), `*`(`^`(`+`(x, `-`(z)), 2), `*`(`^`(z, 2))))) (4.3)
 

> Q14:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q14, `+`(`-`(`*`(4, `*`(`^`(t, 2), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(`^`(U, 3)))))), `-`(`*`(2, `*`(`^`(t, 2), `*`(`+`(`*`(2, `*`(`^`(t, 2))), 1), `*`(U))))), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2), `*...
`:=`(Q14, `+`(`-`(`*`(4, `*`(`^`(t, 2), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(`^`(U, 3)))))), `-`(`*`(2, `*`(`^`(t, 2), `*`(`+`(`*`(2, `*`(`^`(t, 2))), 1), `*`(U))))), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2), `*...
(4.4)
 

> subs(U=1,Q14);
simplify(%);
 

`+`(`-`(`*`(3, `*`(`^`(t, 2), `*`(`+`(`*`(`^`(t, 2)), 1))))), `-`(`*`(2, `*`(`^`(t, 2), `*`(`+`(`*`(2, `*`(`^`(t, 2))), 1))))), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2)), `*`(6, `*`(`^`(t, 4))), `*`(3, `*`(... (4.5)
 

0 (4.5)
 

> Quartic_to_Weierstrass(Q14,[1,0]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(3, `*`(`^`(t, 2))), 5), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`+`(`*`(8, `*`(`^`(t, 2))), 8), `*`(X, `*`(`^`(Z, 2))))), `-`(`*`(4, `*`(`^`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(3, `*`(`^`(t, 2))), 5), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`+`(`*`(8, `*`(`^`(t, 2))), 8), `*`(X, `*`(`^`(Z, 2))))), `-`(`*`(4, `*`(`^`(...
(4.6)
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
(4.7)
 

> step5(%[1],{x=X,z=Z,y=Y},{x,y,z});
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(3, `*`(`^`(t, 2))), 5), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(4, `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2), `*`(`^`(Z, 3))))), `-`(`*`(8, `*`(`+`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(3, `*`(`^`(t, 2))), 5), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(4, `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2), `*`(`^`(Z, 3))))), `-`(`*`(8, `*`(`+`(...
(4.8)
 

> mapfactor(subs({X=X,Y=Y},%[1]),[X,Y]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(3, `*`(`^`(t, 2))), 5), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(4, `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2), `*`(`^`(Z, 3))))), `-`(`*`(8, `*`(`+`(... (4.9)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (4.10)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(3, `*`(`^`(t, 2))), 5), `*`(`^`(x, 2))), `*`(`+`(`*`(8, `*`(`^`(t, 2))), 8), `*`(x)), `*`(4, `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2)))) (4.10)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(3, `*`(`^`(t, 2))), 5), `*`(`^`(x, 2))), `*`(`+`(`*`(8, `*`(`^`(t, 2))), 8), `*`(x)), `*`(4, `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2)))) (4.11)
 

Discriminant = `+`(`-`(`*`(256, `*`(`^`(t, 2), `*`(`+`(`*`(27, `*`(`^`(t, 4))), `*`(18, `*`(`^`(t, 2))), `-`(1)), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2))))))) (4.11)
 

`+`(jay, `-`(invariant)) = `+`(`-`(`/`(`*`(16, `*`(`^`(`+`(`*`(3, `*`(`^`(t, 2))), 1), 6))), `*`(`^`(t, 2), `*`(`+`(`*`(27, `*`(`^`(t, 4))), `*`(18, `*`(`^`(t, 2))), `-`(1)), `*`(`^`(`+`(`*`(`^`(t, 2)... (4.11)
 

`
` (4.11)
 

This is a rational elliptic surface; Oguiso-Shioda type No.14. (4.11)
 

`
` (4.11)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (4.11)
 

`
` (4.11)
 

The rank of the Mordell-Weil group over C is 4. (4.11)
 

` ` (4.11)
 

TypeNo.15 

> qc[15]:=(x^2+y^2-3*x*z)^2-4*x^2*(2*z^2-x*z);
 

`:=`(qc[15], `+`(`*`(`^`(`+`(`*`(`^`(x, 2)), `*`(`^`(y, 2)), `-`(`*`(3, `*`(x, `*`(z))))), 2)), `-`(`*`(4, `*`(`^`(x, 2), `*`(`+`(`*`(2, `*`(`^`(z, 2))), `-`(`*`(x, `*`(z)))))))))) (5.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[15]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[15]),x,y);
 

{[[1, 0, 1], 2, 1, 2], [[0, 0, 1], 2, 2, 2]} (5.2)
 

> subs(y=t*(x+z),qc[15]);
 

`+`(`*`(`^`(`+`(`*`(`^`(x, 2)), `*`(`^`(t, 2), `*`(`^`(`+`(x, z), 2))), `-`(`*`(3, `*`(x, `*`(z))))), 2)), `-`(`*`(4, `*`(`^`(x, 2), `*`(`+`(`*`(2, `*`(`^`(z, 2))), `-`(`*`(x, `*`(z))))))))) (5.3)
 

> Q15:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q15, `+`(`*`(2, `*`(`^`(t, 2), `*`(`+`(`-`(3), `*`(2, `*`(`^`(t, 2)))), `*`(U)))), `*`(`+`(`-`(`*`(10, `*`(`^`(t, 2)))), `*`(6, `*`(`^`(t, 4))), 1), `*`(`^`(U, 2))), `*`(`^`(`+`(`*`(`^`(t, 2)), 1...
`:=`(Q15, `+`(`*`(2, `*`(`^`(t, 2), `*`(`+`(`-`(3), `*`(2, `*`(`^`(t, 2)))), `*`(U)))), `*`(`+`(`-`(`*`(10, `*`(`^`(t, 2)))), `*`(6, `*`(`^`(t, 4))), 1), `*`(`^`(U, 2))), `*`(`^`(`+`(`*`(`^`(t, 2)), 1...
(5.4)
 

> subs(U=-1,Q15);
simplify(%);
 

`+`(`-`(`*`(2, `*`(`^`(t, 2), `*`(`+`(`-`(3), `*`(2, `*`(`^`(t, 2)))))))), `-`(`*`(10, `*`(`^`(t, 2)))), `*`(7, `*`(`^`(t, 4))), 1, `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2)), `-`(`*`(2, `*`(`+`(t, `-`(1)), ... (5.5)
 

4 (5.5)
 

> Quartic_to_Weierstrass(Q15,[-1,2]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(12, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(`-`(192), `-`(`*`(320, `*`(`^`(t, 2))))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(32, `*`(`^`(t, 2))), 1...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(12, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(`-`(192), `-`(`*`(320, `*`(`^`(t, 2))))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(32, `*`(`^`(t, 2))), 1...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(12, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(`-`(192), `-`(`*`(320, `*`(`^`(t, 2))))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(32, `*`(`^`(t, 2))), 1...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(12, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(`-`(192), `-`(`*`(320, `*`(`^`(t, 2))))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(32, `*`(`^`(t, 2))), 1...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(12, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(`-`(192), `-`(`*`(320, `*`(`^`(t, 2))))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(32, `*`(`^`(t, 2))), 1...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(12, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(`-`(192), `-`(`*`(320, `*`(`^`(t, 2))))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(32, `*`(`^`(t, 2))), 1...
(5.6)
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
(5.7)
 

> step5(%[1],{x=X,z=Z,y=Y},{x,y,z});
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(1024, `*`(`+`(`-`(5), `-`(`*`(14, `*`(`^`(t, 2)))), `-`(`*`(5, `*`(`^`(t, 4)))), `*`(8, `*`(`^`(t, 6)))), `*`(`^`(Z, 3)))), `-`(`*`(4, `*`(`+`(`*`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(1024, `*`(`+`(`-`(5), `-`(`*`(14, `*`(`^`(t, 2)))), `-`(`*`(5, `*`(`^`(t, 4)))), `*`(8, `*`(`^`(t, 6)))), `*`(`^`(Z, 3)))), `-`(`*`(4, `*`(`+`(`*`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(1024, `*`(`+`(`-`(5), `-`(`*`(14, `*`(`^`(t, 2)))), `-`(`*`(5, `*`(`^`(t, 4)))), `*`(8, `*`(`^`(t, 6)))), `*`(`^`(Z, 3)))), `-`(`*`(4, `*`(`+`(`*`(...
(5.8)
 

> mapfactor(subs({X=4*X,Y=8*Y},%[1])/64,[X,Y]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`-`(5), `-`(`*`(14, `*`(`^`(t, 2)))), `-`(`*`(5, `*`(`^`(t, 4)))), `*`(8, `*`(`^`(t, 6)))), `*`(`^`(Z, 3)))), `-`(`*`(`+`(`*`(8, `*`(`^...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`-`(5), `-`(`*`(14, `*`(`^`(t, 2)))), `-`(`*`(5, `*`(`^`(t, 4)))), `*`(8, `*`(`^`(t, 6)))), `*`(`^`(Z, 3)))), `-`(`*`(`+`(`*`(8, `*`(`^...
(5.9)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (5.10)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(8, `*`(`^`(t, 2))), 13), `*`(`^`(x, 2))), `*`(`+`(56, `-`(`*`(16, `*`(`^`(t, 4)))), `*`(88, `*`(`^`(t, 2)))), `*`(x)), 80, `*`(224, `*`(`^`(t, 2))), `*... (5.10)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(8, `*`(`^`(t, 2))), 13), `*`(`^`(x, 2))), `*`(`+`(56, `-`(`*`(16, `*`(`^`(t, 4)))), `*`(88, `*`(`^`(t, 2)))), `*`(x)), 80, `*`(224, `*`(`^`(t, 2))), `*... (5.11)
 

Discriminant = `+`(`*`(16384, `*`(`^`(t, 6), `*`(`+`(2, `-`(`*`(119, `*`(`^`(t, 2)))), `-`(`*`(56, `*`(`^`(t, 4)))), `*`(144, `*`(`^`(t, 6)))))))) (5.11)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(`^`(`+`(1, `-`(`*`(56, `*`(`^`(t, 2)))), `*`(112, `*`(`^`(t, 4)))), 3)), `*`(4, `*`(`^`(t, 6), `*`(`+`(2, `-`(`*`(119, `*`(`^`(t, 2)))), `-`(`*`(56, `*`(`^`(t, 4... (5.11)
 

`
` (5.11)
 

This is a rational elliptic surface; Oguiso-Shioda type No.15. (5.11)
 

`
` (5.11)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (5.11)
 

`
` (5.11)
 

The rank of the Mordell-Weil group over C is 3. (5.11)
 

` ` (5.11)
 

TypeNo.16 

> qc[16]:=x^4+y^4+x^3*y-x*y^2*z;
 

`:=`(qc[16], `+`(`*`(`^`(x, 4)), `*`(`^`(y, 4)), `*`(`^`(x, 3), `*`(y)), `-`(`*`(x, `*`(`^`(y, 2), `*`(z)))))) (6.1)
 

`:=`(qc[14], `+`(`*`(`^`(`+`(`*`(`^`(x, 2)), `*`(`^`(y, 2))), 2)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))), `*`(`^`(y, 2), `*`(`^`(z, 2))))) 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[16]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[16]),x,y);
 

{[[0, 0, 1], 3, 3, 2]} (6.2)
 

> subs(z=t*(x-y)+2*y,qc[16]);
 

`+`(`*`(`^`(x, 4)), `*`(`^`(y, 4)), `*`(`^`(x, 3), `*`(y)), `-`(`*`(x, `*`(`^`(y, 2), `*`(`+`(`*`(t, `*`(`+`(x, `-`(y)))), `*`(2, `*`(y)))))))) (6.3)
 

> Q16:=mapfactor(subs({y=1,x=U},%),U);
 

`:=`(Q16, `+`(`*`(`+`(`-`(2), t), `*`(U)), `*`(`^`(U, 4)), `*`(`^`(U, 3)), `-`(`*`(t, `*`(`^`(U, 2)))), 1)) (6.4)
 

> subs(U=1,Q16);
simplify(%);
 

1 (6.5)
 

1 (6.5)
 

> Quartic_to_Weierstrass(Q16,[1,1]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(5, `-`(t)), `*`(X, `*`(Y, `*`(Z)))), `*`(10, `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(`/`(3, 2), `*`(t)), `/`(11, 4), `-`(`*`(`/`(1, 4), `*`(`*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(5, `-`(t)), `*`(X, `*`(Y, `*`(Z)))), `*`(10, `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(`/`(3, 2), `*`(t)), `/`(11, 4), `-`(`*`(`/`(1, 4), `*`(`*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(5, `-`(t)), `*`(X, `*`(Y, `*`(Z)))), `*`(10, `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(`/`(3, 2), `*`(t)), `/`(11, 4), `-`(`*`(`/`(1, 4), `*`(`*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(5, `-`(t)), `*`(X, `*`(Y, `*`(Z)))), `*`(10, `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(`/`(3, 2), `*`(t)), `/`(11, 4), `-`(`*`(`/`(1, 4), `*`(`*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(5, `-`(t)), `*`(X, `*`(Y, `*`(Z)))), `*`(10, `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(`/`(3, 2), `*`(t)), `/`(11, 4), `-`(`*`(`/`(1, 4), `*`(`*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(5, `-`(t)), `*`(X, `*`(Y, `*`(Z)))), `*`(10, `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(`/`(3, 2), `*`(t)), `/`(11, 4), `-`(`*`(`/`(1, 4), `*`(`*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(5, `-`(t)), `*`(X, `*`(Y, `*`(Z)))), `*`(10, `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(`/`(3, 2), `*`(t)), `/`(11, 4), `-`(`*`(`/`(1, 4), `*`(`*...
(6.6)
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
(6.7)
 

> step5(%[1],{x=X,z=Z,y=Y},{x,y,z});
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(64, `*`(`+`(14, `-`(`*`(6, `*`(t))), `*`(`^`(t, 2))), `*`(`^`(Z, 3))))), `*`(4, `*`(`+`(t, `-`(9)), `*`(`^`(X, 2), `*`(Z)))), `*`(16, `*`(`+`(`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(64, `*`(`+`(14, `-`(`*`(6, `*`(t))), `*`(`^`(t, 2))), `*`(`^`(Z, 3))))), `*`(4, `*`(`+`(t, `-`(9)), `*`(`^`(X, 2), `*`(Z)))), `*`(16, `*`(`+`(`...
(6.8)
 

> mapfactor(subs({X=4*X,Y=8*Y},%[1]/64),[X,Y]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(14, `-`(`*`(6, `*`(t))), `*`(`^`(t, 2))), `*`(`^`(Z, 3)))), `*`(`+`(t, `-`(9)), `*`(`^`(X, 2), `*`(Z))), `*`(`+`(`-`(21), `*`(5, `*`(t))), ... (6.9)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (6.10)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(t), 9), `*`(`^`(x, 2))), `*`(`+`(21, `-`(`*`(5, `*`(t)))), `*`(x)), 14, `-`(`*`(6, `*`(t))), `*`(`^`(t, 2))) (6.10)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(t), 9), `*`(`^`(x, 2))), `*`(`+`(21, `-`(`*`(5, `*`(t)))), `*`(x)), 14, `-`(`*`(6, `*`(t))), `*`(`^`(t, 2))) (6.11)
 

Discriminant = `+`(3024, `*`(1728, `*`(t)), `-`(`*`(4032, `*`(`^`(t, 2)))), `*`(1792, `*`(`^`(t, 3))), `-`(`*`(704, `*`(`^`(t, 4)))), `*`(64, `*`(`^`(t, 5)))) (6.11)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(256, `*`(`^`(`+`(18, `-`(`*`(3, `*`(t))), `*`(`^`(t, 2))), 3))), `*`(`+`(189, `*`(108, `*`(t)), `-`(`*`(252, `*`(`^`(t, 2)))), `*`(112, `*`(`^`(t, 3))), `-`(`*`(... (6.11)
 

`
` (6.11)
 

This is a rational elliptic surface; Oguiso-Shioda type No.16. (6.11)
 

`
` (6.11)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi(
Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi(
(6.11)
 

`
` (6.11)
 

The rank of the Mordell-Weil group over C is 3. (6.11)
 

` ` (6.11)
 

> latex(y^2 = x^3+(-t+9)*x^2+(21-5*t)*x+14-6*t+t^2);
 

{y}^{2}={x}^{3}+ \left( -t+9 \right) {x}^{2}+ \left( 21-5\,t \right) x
 

+14-6\,t+{t}^{2}
 

TypeNo.17 

> qc[17]:=(x^2-y*z)^2+y*(4*x^3-x*y^2-y^3);
 

`:=`(qc[17], `+`(`*`(`^`(`+`(`*`(`^`(x, 2)), `-`(`*`(y, `*`(z)))), 2)), `*`(y, `*`(`+`(`*`(4, `*`(`^`(x, 3))), `-`(`*`(`^`(y, 2), `*`(x))), `-`(`*`(`^`(y, 3)))))))) (7.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[17]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[17]),x,y);
 

{[[0, 0, 1], 2, 2, 1]} (7.2)
 

> subs(y=t*x+z,qc[17]);
 

`+`(`*`(`^`(`+`(`*`(`^`(x, 2)), `-`(`*`(`+`(`*`(t, `*`(x)), z), `*`(z)))), 2)), `*`(`+`(`*`(t, `*`(x)), z), `*`(`+`(`*`(4, `*`(`^`(x, 3))), `-`(`*`(`^`(`+`(`*`(t, `*`(x)), z), 2), `*`(x))), `-`(`*`(`^... (7.3)
 

> Q17:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q17, `+`(`-`(`*`(`+`(`*`(2, `*`(t)), 1), `*`(U))), `-`(`*`(`+`(`-`(`*`(4, `*`(t))), `*`(`^`(t, 3)), `*`(`^`(t, 4)), `-`(1)), `*`(`^`(U, 4)))), `-`(`*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(4, `*`(`^`(t...
`:=`(Q17, `+`(`-`(`*`(`+`(`*`(2, `*`(t)), 1), `*`(U))), `-`(`*`(`+`(`-`(`*`(4, `*`(t))), `*`(`^`(t, 3)), `*`(`^`(t, 4)), `-`(1)), `*`(`^`(U, 4)))), `-`(`*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(4, `*`(`^`(t...
(7.4)
 

> subs(U=0,Q17);
simplify(%);
 

0 (7.5)
 

0 (7.5)
 

> Quartic_to_Weierstrass(Q17,[0,0]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(2), `-`(`*`(5, `*`(`^`(t, 2)))), `-`(`*`(3, `*`(t)))), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`+`(`*`(2, `*`(t)), 1), `*`(`+`(`*`(3, `*`(`^`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(2), `-`(`*`(5, `*`(`^`(t, 2)))), `-`(`*`(3, `*`(t)))), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`+`(`*`(2, `*`(t)), 1), `*`(`+`(`*`(3, `*`(`^`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(2), `-`(`*`(5, `*`(`^`(t, 2)))), `-`(`*`(3, `*`(t)))), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`+`(`*`(2, `*`(t)), 1), `*`(`+`(`*`(3, `*`(`^`...
(7.6)
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
(7.7)
 

> step5(%[1],{x=X,z=Z,y=Y},{x,y,z});
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(`+`(2, `*`(5, `*`(`^`(t, 2))), `*`(3, `*`(t))), `*`(`^`(X, 2), `*`(Z))), `-`(`*`(`+`(`*`(2, `*`(t)), 1), `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(4, `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(`+`(2, `*`(5, `*`(`^`(t, 2))), `*`(3, `*`(t))), `*`(`^`(X, 2), `*`(Z))), `-`(`*`(`+`(`*`(2, `*`(t)), 1), `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(4, `*`...
(7.8)
 

> mapfactor(subs({X=X,Y=Y},%[1]),[X,Y]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(`+`(2, `*`(5, `*`(`^`(t, 2))), `*`(3, `*`(t))), `*`(`^`(X, 2), `*`(Z))), `-`(`*`(`+`(`*`(2, `*`(t)), 1), `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(4, `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(`+`(2, `*`(5, `*`(`^`(t, 2))), `*`(3, `*`(t))), `*`(`^`(X, 2), `*`(Z))), `-`(`*`(`+`(`*`(2, `*`(t)), 1), `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(4, `*`...
(7.9)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (7.10)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(2), `-`(`*`(5, `*`(`^`(t, 2)))), `-`(`*`(3, `*`(t)))), `*`(`^`(x, 2))), `*`(`+`(`*`(2, `*`(t)), 1), `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(4, `*`(`^`(t, 3...
`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(2), `-`(`*`(5, `*`(`^`(t, 2)))), `-`(`*`(3, `*`(t)))), `*`(`^`(x, 2))), `*`(`+`(`*`(2, `*`(t)), 1), `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(4, `*`(`^`(t, 3...
(7.10)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(2), `-`(`*`(5, `*`(`^`(t, 2)))), `-`(`*`(3, `*`(t)))), `*`(`^`(x, 2))), `*`(`+`(`*`(2, `*`(t)), 1), `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(4, `*`(`^`(t, 3...
`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(2), `-`(`*`(5, `*`(`^`(t, 2)))), `-`(`*`(3, `*`(t)))), `*`(`^`(x, 2))), `*`(`+`(`*`(2, `*`(t)), 1), `*`(`+`(`*`(3, `*`(`^`(t, 2))), `*`(4, `*`(`^`(t, 3...
(7.11)
 

Discriminant = `+`(`*`(16, `*`(`+`(`*`(16, `*`(`^`(t, 5))), `*`(16, `*`(`^`(t, 4))), `*`(172, `*`(`^`(t, 3))), `*`(828, `*`(`^`(t, 2))), `*`(1212, `*`(t)), 469), `*`(`^`(`+`(`*`(2, `*`(t)), 1), 2))))) (7.11)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(256, `*`(`^`(`+`(16, `*`(8, `*`(`^`(t, 2))), `*`(30, `*`(t)), `*`(`^`(t, 4))), 3))), `*`(`+`(`*`(16, `*`(`^`(t, 5))), `*`(16, `*`(`^`(t, 4))), `*`(172, `*`(`^`(t... (7.11)
 

`
` (7.11)
 

This is a rational elliptic surface; Oguiso-Shioda type No.17. (7.11)
 

`
` (7.11)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi(
Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi(
(7.11)
 

`
` (7.11)
 

The rank of the Mordell-Weil group over C is 3. (7.11)
 

` ` (7.11)
 

TypeNo.18 

> qc[18]:=x^4+y^4-x^2*y*z-x*y^2*z;
 

`:=`(qc[18], `+`(`*`(`^`(x, 4)), `*`(`^`(y, 4)), `-`(`*`(`^`(x, 2), `*`(y, `*`(z)))), `-`(`*`(x, `*`(`^`(y, 2), `*`(z)))))) (8.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[18]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[18]),x,y);
 

{[[0, 0, 1], 3, 3, 3]} (8.2)
 

> subs(y=t*(x-z)+z,qc[18]);
 

`+`(`*`(`^`(x, 4)), `*`(`^`(`+`(`*`(t, `*`(`+`(x, `-`(z)))), z), 4)), `-`(`*`(`^`(x, 2), `*`(`+`(`*`(t, `*`(`+`(x, `-`(z)))), z), `*`(z)))), `-`(`*`(x, `*`(`^`(`+`(`*`(t, `*`(`+`(x, `-`(z)))), z), 2),... (8.3)
 

> Q18:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q18, `+`(`-`(`*`(`^`(`+`(`*`(2, `*`(t)), `-`(1)), 2), `*`(`^`(`+`(t, `-`(1)), 2), `*`(U)))), `*`(`+`(t, `-`(1)), `*`(`+`(`*`(6, `*`(`^`(t, 3))), `-`(`*`(6, `*`(`^`(t, 2)))), `*`(2, `*`(t)), 1), `...
`:=`(Q18, `+`(`-`(`*`(`^`(`+`(`*`(2, `*`(t)), `-`(1)), 2), `*`(`^`(`+`(t, `-`(1)), 2), `*`(U)))), `*`(`+`(t, `-`(1)), `*`(`+`(`*`(6, `*`(`^`(t, 3))), `-`(`*`(6, `*`(`^`(t, 2)))), `*`(2, `*`(t)), 1), `...
(8.4)
 

> subs(U=1,Q18);
simplify(%);
 

`+`(`-`(`*`(`^`(`+`(`*`(2, `*`(t)), `-`(1)), 2), `*`(`^`(`+`(t, `-`(1)), 2)))), `*`(`+`(t, `-`(1)), `*`(`+`(`*`(6, `*`(`^`(t, 3))), `-`(`*`(6, `*`(`^`(t, 2)))), `*`(2, `*`(t)), 1))), `*`(`^`(t, 4)), 1...
`+`(`-`(`*`(`^`(`+`(`*`(2, `*`(t)), `-`(1)), 2), `*`(`^`(`+`(t, `-`(1)), 2)))), `*`(`+`(t, `-`(1)), `*`(`+`(`*`(6, `*`(`^`(t, 3))), `-`(`*`(6, `*`(`^`(t, 2)))), `*`(2, `*`(t)), 1))), `*`(`^`(t, 4)), 1...
(8.5)
 

0 (8.5)
 

> Quartic_to_Weierstrass(Q18,[1,0]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`+`(`-`(`*`(4, `*`(t))), `*`(5, `*`(`^`(t, 2))), 5), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(4, `*`(`^`(t, 2))), `-`(`*`(5, `*`(t))), 4), `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`+`(`-`(`*`(4, `*`(t))), `*`(5, `*`(`^`(t, 2))), 5), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(4, `*`(`^`(t, 2))), `-`(`*`(5, `*`(t))), 4), `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`+`(`-`(`*`(4, `*`(t))), `*`(5, `*`(`^`(t, 2))), 5), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(4, `*`(`^`(t, 2))), `-`(`*`(5, `*`(t))), 4), `*`...
(8.6)
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
(8.7)
 

> step5(%[1],{x=X,z=Z,y=Y},{x,y,z});
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`+`(`-`(`*`(4, `*`(t))), `*`(5, `*`(`^`(t, 2))), 5), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(4, `*`(`^`(t, 2))), `-`(`*`(5, `*`(t))), 4), `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`+`(`-`(`*`(4, `*`(t))), `*`(5, `*`(`^`(t, 2))), 5), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(4, `*`(`^`(t, 2))), `-`(`*`(5, `*`(t))), 4), `*`...
(8.8)
 

> mapfactor(subs({X=X,Y=Y},%[1]),[X,Y]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`+`(`-`(`*`(4, `*`(t))), `*`(5, `*`(`^`(t, 2))), 5), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(4, `*`(`^`(t, 2))), `-`(`*`(5, `*`(t))), 4), `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`+`(`-`(`*`(4, `*`(t))), `*`(5, `*`(`^`(t, 2))), 5), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(4, `*`(`^`(t, 2))), `-`(`*`(5, `*`(t))), 4), `*`...
(8.9)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (8.10)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(`*`(4, `*`(t))), `*`(5, `*`(`^`(t, 2))), 5), `*`(`^`(x, 2))), `*`(`+`(`*`(4, `*`(`^`(t, 2))), `-`(`*`(5, `*`(t))), 4), `*`(`^`(`+`(t, 1), 2), `*`(x))),... (8.10)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(`*`(4, `*`(t))), `*`(5, `*`(`^`(t, 2))), 5), `*`(`^`(x, 2))), `*`(`+`(`*`(4, `*`(`^`(t, 2))), `-`(`*`(5, `*`(t))), 4), `*`(`^`(`+`(t, 1), 2), `*`(x))),... (8.11)
 

Discriminant = `+`(`-`(`*`(16, `*`(`+`(`*`(23, `*`(`^`(t, 4))), `-`(`*`(86, `*`(`^`(t, 3)))), `*`(125, `*`(`^`(t, 2))), `-`(`*`(86, `*`(t))), 23), `*`(`^`(`+`(t, 1), 2), `*`(`^`(`+`(t, `-`(1)), 6)))))... (8.11)
 

`+`(jay, `-`(invariant)) = `+`(`-`(`/`(`*`(256, `*`(`^`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(`*`(23, `*`(t))), 13), 3))), `*`(`+`(`*`(23, `*`(`^`(t, 4))), `-`(`*`(86, `*`(`^`(t, 3)))), `*`(125, `*`(`^`(t,... (8.11)
 

`
` (8.11)
 

This is a rational elliptic surface; Oguiso-Shioda type No.18. (8.11)
 

`
` (8.11)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (8.11)
 

`
` (8.11)
 

The rank of the Mordell-Weil group over C is 3. (8.11)
 

` ` (8.11)
 

TypeNo.19 

> qc[19]:=x^4+y^4-x^2*z^2;
 

`:=`(qc[19], `+`(`*`(`^`(x, 4)), `*`(`^`(y, 4)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))))) (9.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[19]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[19]),x,y);
 

{[[0, 0, 1], 2, 2, 2]} (9.2)
 

> subs(y=t*(x-z),qc[19]);
 

`+`(`*`(`^`(x, 4)), `*`(`^`(t, 4), `*`(`^`(`+`(x, `-`(z)), 4))), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2))))) (9.3)
 

> Q19:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q19, `+`(`-`(`*`(4, `*`(`^`(t, 4), `*`(U)))), `*`(`+`(1, `*`(`^`(t, 4))), `*`(`^`(U, 4))), `-`(`*`(4, `*`(`^`(t, 4), `*`(`^`(U, 3))))), `*`(`+`(`*`(6, `*`(`^`(t, 4))), `-`(1)), `*`(`^`(U, 2))), `... (9.4)
 

> subs(U=1,Q19);
simplify(%);
 

0 (9.5)
 

0 (9.5)
 

> Quartic_to_Weierstrass(Q19,[1,0]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(5, `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(8, `*`(X, `*`(`^`(Z, 2))))), `-`(`*`(`+`(4, `*`(4, `*`(`^`(t, 4)))), `*`(`^`(Z, 3))))), {X = `+`(`*`(2, `*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(5, `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(8, `*`(X, `*`(`^`(Z, 2))))), `-`(`*`(`+`(4, `*`(4, `*`(`^`(t, 4)))), `*`(`^`(Z, 3))))), {X = `+`(`*`(2, `*...
(9.6)
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
(9.7)
 

> step5(%[1],{x=X,z=Z,y=Y},{x,y,z});
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(5, `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(8, `*`(X, `*`(`^`(Z, 2))))), `-`(`*`(4, `*`(`+`(1, `*`(`^`(t, 4))), `*`(`^`(Z, 3)))))), {x = X, y = Y, z =... (9.8)
 

> mapfactor(subs({X=X,Y=Y},%[1]),[X,Y]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(5, `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(8, `*`(X, `*`(`^`(Z, 2))))), `-`(`*`(4, `*`(`+`(1, `*`(`^`(t, 4))), `*`(`^`(Z, 3)))))) (9.9)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (9.10)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(5, `*`(`^`(x, 2))), `*`(8, `*`(x)), 4, `*`(4, `*`(`^`(t, 4)))) (9.10)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(5, `*`(`^`(x, 2))), `*`(8, `*`(x)), 4, `*`(4, `*`(`^`(t, 4)))) (9.11)
 

Discriminant = `+`(`-`(`*`(256, `*`(`^`(t, 4), `*`(`+`(`-`(1), `*`(27, `*`(`^`(t, 4))))))))) (9.11)
 

`+`(jay, `-`(invariant)) = `+`(`-`(`/`(`*`(16), `*`(`^`(t, 4), `*`(`+`(`-`(1), `*`(27, `*`(`^`(t, 4))))))))) (9.11)
 

`
` (9.11)
 

This is a rational elliptic surface; Oguiso-Shioda type No.19. (9.11)
 

`
` (9.11)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (9.11)
 

`
` (9.11)
 

The rank of the Mordell-Weil group over C is 3. (9.11)
 

` ` (9.11)
 

` ` (9.12)
 

TypeNo.20 

> qc[20]:=(x^2+y^2-2*x*z)^2-x^2*z^2-y^2*z^2;
 

`:=`(qc[20], `+`(`*`(`^`(`+`(`*`(`^`(x, 2)), `*`(`^`(y, 2)), `-`(`*`(2, `*`(x, `*`(z))))), 2)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))), `-`(`*`(`^`(y, 2), `*`(`^`(z, 2)))))) (10.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[20]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[20]),x,y);
 

{[[RootOf(`+`(`*`(`^`(_Z, 2)), 1)), 1, 0], 2, 1, 1], [[0, 0, 1], 2, 1, 2]} (10.2)
 

> subs(y=t*(x-2*z),qc[20]);
 

`+`(`*`(`^`(`+`(`*`(`^`(x, 2)), `*`(`^`(t, 2), `*`(`^`(`+`(x, `-`(`*`(2, `*`(z)))), 2))), `-`(`*`(2, `*`(x, `*`(z))))), 2)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))), `-`(`*`(`^`(t, 2), `*`(`^`(`+`(x, `-`(... (10.3)
 

> Q20:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q20, `+`(`-`(`*`(4, `*`(`^`(t, 2), `*`(`+`(`*`(8, `*`(`^`(t, 2))), 3), `*`(U))))), `*`(`+`(3, `*`(24, `*`(`^`(t, 4))), `*`(23, `*`(`^`(t, 2)))), `*`(`^`(U, 2))), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2...
`:=`(Q20, `+`(`-`(`*`(4, `*`(`^`(t, 2), `*`(`+`(`*`(8, `*`(`^`(t, 2))), 3), `*`(U))))), `*`(`+`(3, `*`(24, `*`(`^`(t, 4))), `*`(23, `*`(`^`(t, 2)))), `*`(`^`(U, 2))), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2...
(10.4)
 

> subs(U=2,Q20);
simplify(%);
 

`+`(`-`(`*`(8, `*`(`^`(t, 2), `*`(`+`(`*`(8, `*`(`^`(t, 2))), 3))))), 12, `*`(96, `*`(`^`(t, 4))), `*`(92, `*`(`^`(t, 2))), `*`(16, `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2))), `-`(`*`(32, `*`(`+`(1, `*`(2, ...
`+`(`-`(`*`(8, `*`(`^`(t, 2), `*`(`+`(`*`(8, `*`(`^`(t, 2))), 3))))), 12, `*`(96, `*`(`^`(t, 4))), `*`(92, `*`(`^`(t, 2))), `*`(16, `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2))), `-`(`*`(32, `*`(`+`(1, `*`(2, ...
(10.5)
 

-4 (10.5)
 

> Quartic_to_Weierstrass(Q20,[2,2*I]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(128, `*`(128, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`+`(`-`(2), t), `*`(`+`(t, 2), `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(128, `*`(128, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`+`(`-`(2), t), `*`(`+`(t, 2), `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(128, `*`(128, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`+`(`-`(2), t), `*`(`+`(t, 2), `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(128, `*`(128, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`+`(`-`(2), t), `*`(`+`(t, 2), `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(128, `*`(128, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`+`(`-`(2), t), `*`(`+`(t, 2), `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(128, `*`(128, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`+`(`-`(2), t), `*`(`+`(t, 2), `*`...
(10.6)
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(16, `*`(`+`(`*`(`^`(t, 4)), `-`(`*`(`^`(t, 3))), `*`(4, `*`(`^`(t, 2))), `-`(t), 1), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), 1), `...
(10.7)
 

> step5(%[1],{x=X,z=Z,y=Y},{x,y,z});
 

`+`(`-`(`*`(1024, `*`(`^`(t, 2), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2), `*`(`^`(Z, 3)))))), `-`(`*`(`^`(X, 3))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(`+`(`*`(`^`(t, 2)), `-`(3)), `*`(`^`(X, 2), `*`(Z))...
`+`(`-`(`*`(1024, `*`(`^`(t, 2), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2), `*`(`^`(Z, 3)))))), `-`(`*`(`^`(X, 3))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(`+`(`*`(`^`(t, 2)), `-`(3)), `*`(`^`(X, 2), `*`(Z))...
(10.8)
 

> mapfactor(subs({X=4*X,Y=8*Y},%[1])/64,[X,Y]);
 

`+`(`-`(`*`(16, `*`(`^`(t, 2), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2), `*`(`^`(Z, 3)))))), `-`(`*`(`^`(X, 3))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`+`(`*`(`^`(t, 2)), `-`(3)), `*`(`^`(X, 2), `*`(Z)))), `-`(`... (10.9)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (10.10)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(`^`(t, 2)), `-`(3)), `*`(`^`(x, 2))), `*`(16, `*`(`^`(t, 2), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(x)))), `*`(16, `*`(`^`(t, 2), `*`(`^`(`+`(`*`(`^`(t, 2)), ... (10.10)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(`^`(t, 2)), `-`(3)), `*`(`^`(x, 2))), `*`(16, `*`(`^`(t, 2), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(x)))), `*`(16, `*`(`^`(t, 2), `*`(`^`(`+`(`*`(`^`(t, 2)), ... (10.11)
 

Discriminant = `+`(`-`(`*`(1024, `*`(`^`(t, 2), `*`(`+`(`*`(289, `*`(`^`(t, 4))), `*`(342, `*`(`^`(t, 2))), `-`(27)), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 3))))))) (10.11)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(4, `*`(`^`(`+`(`-`(9), `*`(54, `*`(`^`(t, 2))), `*`(47, `*`(`^`(t, 4)))), 3))), `*`(`^`(t, 2), `*`(`+`(`*`(289, `*`(`^`(t, 4))), `*`(342, `*`(`^`(t, 2))), `-`(27... (10.11)
 

`
` (10.11)
 

This is a rational elliptic surface; Oguiso-Shioda type No.20. (10.11)
 

`
` (10.11)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (10.11)
 

`
` (10.11)
 

The rank of the Mordell-Weil group over C is 3. (10.11)
 

` ` (10.11)