Type1-10.mws

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

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

> with(algcurves):
 

Type No. 1 

> QC[1]:=x^4+y^4-z^4;
 

`:=`(QC[1], `+`(`*`(`^`(x, 4)), `*`(`^`(y, 4)), `-`(`*`(`^`(z, 4))))) (1.1)
 

> plot_real_curve(subs(z=1,QC[1]),x,y);
 

Plot_2d
 

> mapfactor(subs({z=1,x=U},subs(y=t*(x-2*z),QC[1])),U);
 

`+`(`-`(`*`(32, `*`(`^`(t, 4), `*`(U)))), `*`(24, `*`(`^`(t, 4), `*`(`^`(U, 2)))), `*`(`+`(`*`(`^`(t, 4)), 1), `*`(`^`(U, 4))), `-`(`*`(8, `*`(`^`(t, 4), `*`(`^`(U, 3))))), `*`(`+`(`*`(2, `*`(t)), `-`... (1.2)
 

> factor(subs(U=1,%));
 

`*`(`^`(t, 4)) (1.3)
 

> Quartic_to_Weierstrass(%%,[1,t^2]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(Y, `*`(Z)))))))), `-`(`*`(8, `*`(`^`(t, 8), `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(Y, `*`(Z)))))))), `-`(`*`(8, `*`(`^`(t, 8), `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(Y, `*`(Z)))))))), `-`(`*`(8, `*`(`^`(t, 8), `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(Y, `*`(Z)))))))), `-`(`*`(8, `*`(`^`(t, 8), `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(Y, `*`(Z)))))))), `-`(`*`(8, `*`(`^`(t, 8), `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(Y, `*`(Z)))))))), `-`(`*`(8, `*`(`^`(t, 8), `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(Y, `*`(Z)))))))), `-`(`*`(8, `*`(`^`(t, 8), `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(Y, `*`(Z)))))))), `-`(`*`(8, `*`(`^`(t, 8), `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`+`(...
(1.4)
 

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`^`(t, 8), `*`(`+`(`*`(3, `*`(`^`(t, 8))), `-`(`*`(9, `*`(`^`(t, 4)))), 4), `*`(`^`(Z, 2), `*`(X)))))), `-`(`*`(6, `*`(`^`(t, 4), `*`(`+...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`^`(t, 8), `*`(`+`(`*`(3, `*`(`^`(t, 8))), `-`(`*`(9, `*`(`^`(t, 4)))), 4), `*`(`^`(Z, 2), `*`(X)))))), `-`(`*`(6, `*`(`^`(t, 4), `*`(`+...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`^`(t, 8), `*`(`+`(`*`(3, `*`(`^`(t, 8))), `-`(`*`(9, `*`(`^`(t, 4)))), 4), `*`(`^`(Z, 2), `*`(X)))))), `-`(`*`(6, `*`(`^`(t, 4), `*`(`+...
(1.5)
 

> mapfactor(subs({X=t^4*X,Y=t^6*Y},%[1])/t^12,[X,Y]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`+`(`*`(3, `*`(`^`(t, 8))), `-`(`*`(9, `*`(`^`(t, 4)))), 4), `*`(`^`(Z, 2), `*`(X))))), `-`(`*`(6, `*`(`+`(`*`(`^`(t, 4)), 1), `*`(`^`(X...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`+`(`*`(3, `*`(`^`(t, 8))), `-`(`*`(9, `*`(`^`(t, 4)))), 4), `*`(`^`(Z, 2), `*`(X))))), `-`(`*`(6, `*`(`+`(`*`(`^`(t, 4)), 1), `*`(`^`(X...
(1.6)
 

> Elliptic_surface(%):
Show_data();
 

`
     The curve you have entered is:` (1.7)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(6, `*`(`^`(t, 4))), 6), `*`(`^`(x, 2))), `*`(`+`(16, `*`(12, `*`(`^`(t, 8))), `-`(`*`(36, `*`(`^`(t, 4))))), `*`(x)), 16, `*`(8, `*`(`^`(t, 12))), `-`(... (1.7)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(6, `*`(`^`(t, 4))), 6), `*`(`^`(x, 2))), `*`(`+`(16, `*`(12, `*`(`^`(t, 8))), `-`(`*`(36, `*`(`^`(t, 4))))), `*`(x)), 16, `*`(8, `*`(`^`(t, 12))), `-`(... (1.7)
 

Discriminant = `+`(`-`(4096), `*`(184320, `*`(`^`(t, 4))), `-`(`*`(4534272, `*`(`^`(t, 8)))), `*`(13824000, `*`(`^`(t, 12)))) (1.7)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(1728, `*`(`^`(`+`(`-`(1), `*`(15, `*`(`^`(t, 4)))), 3))), `*`(`+`(`-`(1), `*`(45, `*`(`^`(t, 4))), `-`(`*`(1107, `*`(`^`(t, 8)))), `*`(3375, `*`(`^`(t, 12))))))) (1.7)
 

`
` (1.7)
 

This is a rational elliptic surface; Oguiso-Shioda type No.1. (1.7)
 

`
` (1.7)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (1.7)
 

`
` (1.7)
 

The rank of the Mordell-Weil group over C is 8. (1.7)
 

` ` (1.7)
 

Type No. 2 

> QC[2]:=x^4+y^4-2*z^4;
 

`:=`(QC[2], `+`(`*`(`^`(x, 4)), `*`(`^`(y, 4)), `-`(`*`(2, `*`(`^`(z, 4)))))) (2.1)
 

> mapfactor(subs({z=1,x=U},subs(y=t*(x-z)+z,QC[2])),U);
 

`+`(`-`(`*`(4, `*`(t, `*`(`^`(`+`(t, `-`(1)), 3), `*`(U))))), `*`(6, `*`(`^`(t, 2), `*`(`^`(`+`(t, `-`(1)), 2), `*`(`^`(U, 2))))), `-`(`*`(4, `*`(`^`(t, 3), `*`(`+`(t, `-`(1)), `*`(`^`(U, 3)))))), `*`...
`+`(`-`(`*`(4, `*`(t, `*`(`^`(`+`(t, `-`(1)), 3), `*`(U))))), `*`(6, `*`(`^`(t, 2), `*`(`^`(`+`(t, `-`(1)), 2), `*`(`^`(U, 2))))), `-`(`*`(4, `*`(`^`(t, 3), `*`(`+`(t, `-`(1)), `*`(`^`(U, 3)))))), `*`...
(2.2)
 

> Quartic_to_Weierstrass(%/2,[1,0]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(3, `*`(3, `*`(`^`(t, 2)))), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(4, `*`(`+`(`*`(`^`(t, 2)), `-`(t), 1), `*`(`^`(`+`(t, 1), 2), `*`(`^`(Z, 2), ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(3, `*`(3, `*`(`^`(t, 2)))), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(4, `*`(`+`(`*`(`^`(t, 2)), `-`(t), 1), `*`(`^`(`+`(t, 1), 2), `*`(`^`(Z, 2), ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(3, `*`(3, `*`(`^`(t, 2)))), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(4, `*`(`+`(`*`(`^`(t, 2)), `-`(t), 1), `*`(`^`(`+`(t, 1), 2), `*`(`^`(Z, 2), ...
(2.3)
 

> Elliptic_surface(%):
Show_data();
 

`
     The curve you have entered is:` (2.4)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(3, `*`(3, `*`(`^`(t, 2)))), `*`(`^`(x, 2))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), `-`(t), 1), `*`(`^`(`+`(t, 1), 2), `*`(x)))), `*`(2, `*`(`+`(`*`(`^`(t, 4)), 1)... (2.4)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(3, `*`(3, `*`(`^`(t, 2)))), `*`(`^`(x, 2))), `*`(4, `*`(`+`(`*`(`^`(t, 2)), `-`(t), 1), `*`(`^`(`+`(t, 1), 2), `*`(x)))), `*`(2, `*`(`+`(`*`(`^`(t, 4)), 1)... (2.4)
 

Discriminant = `+`(`-`(`*`(64, `*`(`+`(`*`(`^`(t, 10)), `*`(10, `*`(`^`(t, 9))), `*`(9, `*`(`^`(t, 8))), `-`(`*`(96, `*`(`^`(t, 7)))), `*`(210, `*`(`^`(t, 6))), `-`(`*`(252, `*`(`^`(t, 5)))), `-`(`*`(...
Discriminant = `+`(`-`(`*`(64, `*`(`+`(`*`(`^`(t, 10)), `*`(10, `*`(`^`(t, 9))), `*`(9, `*`(`^`(t, 8))), `-`(`*`(96, `*`(`^`(t, 7)))), `*`(210, `*`(`^`(t, 6))), `-`(`*`(252, `*`(`^`(t, 5)))), `-`(`*`(...
(2.4)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(1728, `*`(`^`(`+`(1, `-`(`*`(6, `*`(`^`(t, 2)))), `*`(`^`(t, 4)), `*`(4, `*`(t)), `*`(4, `*`(`^`(t, 3)))), 3))), `*`(`+`(`*`(`^`(t, 10)), `*`(10, `*`(`^`(t, 9)))...
`+`(jay, `-`(invariant)) = `+`(`/`(`*`(1728, `*`(`^`(`+`(1, `-`(`*`(6, `*`(`^`(t, 2)))), `*`(`^`(t, 4)), `*`(4, `*`(t)), `*`(4, `*`(`^`(t, 3)))), 3))), `*`(`+`(`*`(`^`(t, 10)), `*`(10, `*`(`^`(t, 9)))...
(2.4)
 

`
` (2.4)
 

This is a rational elliptic surface; Oguiso-Shioda type No.2. (2.4)
 

`
` (2.4)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi(
Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi(
Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi(
(2.4)
 

`
` (2.4)
 

The rank of the Mordell-Weil group over C is 7. (2.4)
 

` ` (2.4)
 

> ifactor(discrim(Show(Disc)/(t+1)^2,t));
 

`+`(`-`(`*`(`^`(``(2), 159), `*`(`^`(``(3), 27))))) (2.5)
 

> factor(Show(Disc) mod 3);
 

`+`(`*`(2, `*`(`+`(`*`(`^`(t, 2)), `-`(t), 1), `*`(`+`(`*`(`^`(t, 6)), `-`(`*`(`^`(t, 3))), 1), `*`(`^`(`+`(t, 1), 4)))))) (2.6)
 

Type No. 3 

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

`+`(`-`(`*`(4, `*`(`^`(t, 4), `*`(U)))), `*`(6, `*`(`^`(t, 4), `*`(`^`(U, 2)))), `-`(`*`(4, `*`(`^`(t, 4), `*`(`^`(U, 3))))), `*`(`+`(`*`(`^`(t, 4)), 1), `*`(`^`(U, 4))), `*`(`+`(t, `-`(1)), `*`(`+`(t... (3.1)
 

> Quartic_to_Weierstrass(%/2,[1,0]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(3, `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(4, `*`(`^`(Z, 2), `*`(X)))), `-`(`*`(`+`(`*`(2, `*`(`^`(t, 4))), 2), `*`(`^`(Z, 3))))), {Z = `*`(`^`(`+`(U...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(3, `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(4, `*`(`^`(Z, 2), `*`(X)))), `-`(`*`(`+`(`*`(2, `*`(`^`(t, 4))), 2), `*`(`^`(Z, 3))))), {Z = `*`(`^`(`+`(U...
(3.2)
 

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

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

> Elliptic_surface(%):
Show_data();
 

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

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

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

Discriminant = `+`(`-`(64), `-`(`*`(1728, `*`(`^`(t, 8))))) (3.4)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(1728), `*`(`+`(1, `*`(27, `*`(`^`(t, 8))))))) (3.4)
 

`
` (3.4)
 

This is a rational elliptic surface; Oguiso-Shioda type No.3. (3.4)
 

`
` (3.4)
 

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

`
` (3.4)
 

The rank of the Mordell-Weil group over C is 6. (3.4)
 

` ` (3.4)
 

 

`+`(`*`(`^`(x, 4)), `*`(`^`(y, 4)), `-`(`*`(`^`(z, 4)))) (3.5)
 

Type No. 4 

> QC[3]:=x^4+y^4+x^2*z^2-y^2*z^2;
 

`:=`(QC[3], `+`(`*`(`^`(x, 4)), `*`(`^`(y, 4)), `*`(`^`(x, 2), `*`(`^`(z, 2))), `-`(`*`(`^`(y, 2), `*`(`^`(z, 2)))))) (4.1)
 

> plot_real_curve(subs(z=1,QC[3]),x,y);
 

Plot_2d
 

> mapfactor(subs({x=U,z=1},subs(y=t*x+z,QC[3])),U);
 

`+`(`*`(2, `*`(t, `*`(U))), `*`(4, `*`(`^`(t, 3), `*`(`^`(U, 3)))), `*`(`+`(`*`(`^`(t, 4)), 1), `*`(`^`(U, 4))), `*`(`+`(`*`(5, `*`(`^`(t, 2))), 1), `*`(`^`(U, 2)))) (4.2)
 

> Quartic_to_Weierstrass(%,[0,0]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(5, `*`(`^`(t, 2))), 1), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(8, `*`(`^`(t, 4), `*`(X, `*`(`^`(Z, 2)))))), `-`(`*`(4, `*`(`+`(`*`(`^`(t, 4)...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(5, `*`(`^`(t, 2))), 1), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(8, `*`(`^`(t, 4), `*`(X, `*`(`^`(Z, 2)))))), `-`(`*`(4, `*`(`+`(`*`(`^`(t, 4)...
(4.3)
 

> Elliptic_surface(%):
Show_data();
 

`
     The curve you have entered is:` (4.4)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(5, `*`(`^`(t, 2))), 1), `*`(`^`(x, 2))), `*`(8, `*`(`^`(t, 4), `*`(x))), `*`(4, `*`(`^`(t, 2), `*`(`+`(`*`(`^`(t, 4)), 1))))) (4.4)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(5, `*`(`^`(t, 2))), 1), `*`(`^`(x, 2))), `*`(8, `*`(`^`(t, 4), `*`(x))), `*`(4, `*`(`^`(t, 2), `*`(`+`(`*`(`^`(t, 4)), 1))))) (4.4)
 

Discriminant = `+`(`*`(256, `*`(`^`(t, 2), `*`(`+`(`-`(1), `-`(`*`(42, `*`(`^`(t, 2)))), `-`(`*`(40, `*`(`^`(t, 4)))), `-`(`*`(10, `*`(`^`(t, 6)))), `*`(`^`(t, 8))))))) (4.4)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(16, `*`(`^`(`+`(1, `*`(10, `*`(`^`(t, 2))), `*`(`^`(t, 4))), 3))), `*`(`^`(t, 2), `*`(`+`(`-`(1), `-`(`*`(42, `*`(`^`(t, 2)))), `-`(`*`(40, `*`(`^`(t, 4)))), `-`... (4.4)
 

`
` (4.4)
 

This is a rational elliptic surface; Oguiso-Shioda type No.4. (4.4)
 

`
` (4.4)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (4.4)
 

`
` (4.4)
 

The rank of the Mordell-Weil group over C is 6. (4.4)
 

` ` (4.4)
 

Type No. 5 

> QC[4]:=x^4+y^4-x^3*z-x^2*z^2;
 

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

> plot_real_curve(subs(z=1,QC[4]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,x^4+y^4-x^3*z-x^2*z^2),x,y);
 

{[[0, 0, 1], 2, 2, 2]} (5.2)
 

> subs({x=1,y=U},subs(z=y*t*2,x^4+y^4-x^3*z-x^2*z^2));
 

`+`(1, `*`(`^`(U, 4)), `-`(`*`(2, `*`(t, `*`(U)))), `-`(`*`(4, `*`(`^`(U, 2), `*`(`^`(t, 2)))))) (5.3)
 

> Quartic_to_Weierstrass(%,[0,1]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(2, `*`(t, `*`(X, `*`(Y, `*`(Z)))))), `-`(`*`(`^`(X, 3))), `*`(5, `*`(`^`(t, 2), `*`(`^`(X, 2), `*`(Z)))), `*`(4, `*`(X, `*`(`^`(Z, 2)))), `-`(`*`(20, `*`(`^`(t, 2),...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(2, `*`(t, `*`(X, `*`(Y, `*`(Z)))))), `-`(`*`(`^`(X, 3))), `*`(5, `*`(`^`(t, 2), `*`(`^`(X, 2), `*`(Z)))), `*`(4, `*`(X, `*`(`^`(Z, 2)))), `-`(`*`(20, `*`(`^`(t, 2),...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(2, `*`(t, `*`(X, `*`(Y, `*`(Z)))))), `-`(`*`(`^`(X, 3))), `*`(5, `*`(`^`(t, 2), `*`(`^`(X, 2), `*`(Z)))), `*`(4, `*`(X, `*`(`^`(Z, 2)))), `-`(`*`(20, `*`(`^`(t, 2),...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(2, `*`(t, `*`(X, `*`(Y, `*`(Z)))))), `-`(`*`(`^`(X, 3))), `*`(5, `*`(`^`(t, 2), `*`(`^`(X, 2), `*`(Z)))), `*`(4, `*`(X, `*`(`^`(Z, 2)))), `-`(`*`(20, `*`(`^`(t, 2),...
(5.4)
 

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(4, `*`(`^`(t, 2), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`^`(X, 3))), `*`(4, `*`(X, `*`(`^`(Z, 2)))), `-`(`*`(20, `*`(`^`(t, 2), `*`(`^`(Z, 3)))))), {x = X, z = Z, y = `+`(Y... (5.5)
 

> Elliptic_surface(%):
Show_data();
 

`
     The curve you have entered is:` (5.6)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `-`(`*`(4, `*`(`^`(t, 2), `*`(`^`(x, 2))))), `-`(`*`(4, `*`(x))), `*`(20, `*`(`^`(t, 2)))) (5.6)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `-`(`*`(4, `*`(`^`(t, 2), `*`(`^`(x, 2))))), `-`(`*`(4, `*`(x))), `*`(20, `*`(`^`(t, 2)))) (5.6)
 

Discriminant = `+`(`*`(81920, `*`(`^`(t, 8))), `-`(`*`(76544, `*`(`^`(t, 4)))), 4096) (5.6)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(1024, `*`(`^`(`+`(`*`(4, `*`(`^`(t, 4))), 3), 3))), `*`(`+`(`*`(320, `*`(`^`(t, 8))), `-`(`*`(299, `*`(`^`(t, 4)))), 16)))) (5.6)
 

`
` (5.6)
 

This is a rational elliptic surface; Oguiso-Shioda type No.5. (5.6)
 

`
` (5.6)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (5.6)
 

`
` (5.6)
 

The rank of the Mordell-Weil group over C is 5. (5.6)
 

` ` (5.6)
 

Type No. 6 

> QC[5]:=x^4+y^4-y^2*z^2-x^3*z;
 

`:=`(QC[5], `+`(`*`(`^`(x, 4)), `*`(`^`(y, 4)), `-`(`*`(`^`(y, 2), `*`(`^`(z, 2)))), `-`(`*`(`^`(x, 3), `*`(z))))) (6.1)
 

> plot_real_curve(subs(z=1,QC[5]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,QC[5]),x,y);
 

{[[0, 0, 1], 2, 1, 1]} (6.2)
 

> mapfactor(subs({x=U,z=1},subs(y=t*(x-z),QC[5])),U);
 

`+`(`-`(`*`(2, `*`(`^`(t, 2), `*`(`+`(`*`(2, `*`(`^`(t, 2))), `-`(1)), `*`(U))))), `-`(`*`(`+`(1, `-`(`*`(2, `*`(t))), `*`(2, `*`(`^`(t, 2)))), `*`(`+`(1, `*`(2, `*`(t)), `*`(2, `*`(`^`(t, 2)))), `*`(...
`+`(`-`(`*`(2, `*`(`^`(t, 2), `*`(`+`(`*`(2, `*`(`^`(t, 2))), `-`(1)), `*`(U))))), `-`(`*`(`+`(1, `-`(`*`(2, `*`(t))), `*`(2, `*`(`^`(t, 2)))), `*`(`+`(1, `*`(2, `*`(t)), `*`(2, `*`(`^`(t, 2)))), `*`(...
(6.3)
 

> Quartic_to_Weierstrass(%,[1,0]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(3, `-`(`*`(`^`(t, 2)))), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(3, `*`(X, `*`(`^`(Z, 2))))), `-`(`*`(`+`(1, `*`(`^`(t, 4))), `*`(`^`(Z, 3))))), ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(3, `-`(`*`(`^`(t, 2)))), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(3, `*`(X, `*`(`^`(Z, 2))))), `-`(`*`(`+`(1, `*`(`^`(t, 4))), `*`(`^`(Z, 3))))), ...
(6.4)
 

> Elliptic_surface(%);
Show_data();
 

`
     The curve you have entered is:` (6.5)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(3, `-`(`*`(`^`(t, 2)))), `*`(`^`(x, 2))), `*`(3, `*`(x)), 1, `*`(`^`(t, 4))) (6.5)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(3, `-`(`*`(`^`(t, 2)))), `*`(`^`(x, 2))), `*`(3, `*`(x)), 1, `*`(`^`(t, 4))) (6.5)
 

Discriminant = `+`(`*`(16, `*`(`^`(t, 4), `*`(`+`(`*`(58, `*`(`^`(t, 2))), `-`(`*`(63, `*`(`^`(t, 4)))), `*`(4, `*`(`^`(t, 6))), `-`(27)))))) (6.5)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(256, `*`(`^`(t, 2), `*`(`^`(`+`(`-`(6), `*`(`^`(t, 2))), 3)))), `*`(`+`(`*`(58, `*`(`^`(t, 2))), `-`(`*`(63, `*`(`^`(t, 4)))), `*`(4, `*`(`^`(t, 6))), `-`(27))))... (6.5)
 

`
` (6.5)
 

This is a rational elliptic surface; Oguiso-Shioda type No.6. (6.5)
 

`
` (6.5)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (6.5)
 

`
` (6.5)
 

The rank of the Mordell-Weil group over C is 5. (6.5)
 

` ` (6.5)
 

Type No. 7 

> QC[6]:=(x^2+y^2)^2-x^2*z^2+y^2*z^2;
 

`:=`(QC[6], `+`(`*`(`^`(`+`(`*`(`^`(x, 2)), `*`(`^`(y, 2))), 2)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))), `*`(`^`(y, 2), `*`(`^`(z, 2))))) (7.1)
 

> plot_real_curve(subs(z=1,QC[6]),x,y);
 

Plot_2d
 

> mapfactor(subs({z=1,x=U},subs(y=t*x+z,QC[6])),U);
 

`+`(`*`(6, `*`(t, `*`(U))), `*`(`+`(`*`(7, `*`(`^`(t, 2))), 1), `*`(`^`(U, 2))), `*`(4, `*`(t, `*`(`+`(`*`(`^`(t, 2)), 1), `*`(`^`(U, 3))))), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2), `*`(`^`(U, 4))), 2) (7.2)
 

> Quartic_to_Weierstrass(%/2,[0,1]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(3, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(4, `*`(t, `*`(`+`(`*`(`^`(t, 2)), 1), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`/`(`*`(5, `*`(`^`(t, 2))), `*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(3, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(4, `*`(t, `*`(`+`(`*`(`^`(t, 2)), 1), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`/`(`*`(5, `*`(`^`(t, 2))), `*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(3, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(4, `*`(t, `*`(`+`(`*`(`^`(t, 2)), 1), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`/`(`*`(5, `*`(`^`(t, 2))), `*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(3, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(4, `*`(t, `*`(`+`(`*`(`^`(t, 2)), 1), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`/`(`*`(5, `*`(`^`(t, 2))), `*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(3, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(4, `*`(t, `*`(`+`(`*`(`^`(t, 2)), 1), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`/`(`*`(5, `*`(`^`(t, 2))), `*...
(7.3)
 

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(32, `*`(`+`(`*`(2, `*`(`^`(t, 2))), `-`(1)), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(`^`(Z, 2))))))), `-`(`*`(32, `*`(`+`(`*`(3, `*`(`^`(t, 2)))...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(32, `*`(`+`(`*`(2, `*`(`^`(t, 2))), `-`(1)), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(`^`(Z, 2))))))), `-`(`*`(32, `*`(`+`(`*`(3, `*`(`^`(t, 2)))...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(32, `*`(`+`(`*`(2, `*`(`^`(t, 2))), `-`(1)), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(`^`(Z, 2))))))), `-`(`*`(32, `*`(`+`(`*`(3, `*`(`^`(t, 2)))...
(7.4)
 

> Elliptic_surface(%);
Show_data();
 

`
     The curve you have entered is:` (7.5)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(2, `*`(14, `*`(`^`(t, 2)))), `*`(`^`(x, 2))), `*`(32, `*`(`+`(`*`(2, `*`(`^`(t, 2))), `-`(1)), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(x)))), `*`(32, `*`(`+`(`*`(3... (7.5)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(2, `*`(14, `*`(`^`(t, 2)))), `*`(`^`(x, 2))), `*`(32, `*`(`+`(`*`(2, `*`(`^`(t, 2))), `-`(1)), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(x)))), `*`(32, `*`(`+`(`*`(3... (7.5)
 

Discriminant = `+`(`-`(`*`(16384, `*`(`+`(`*`(`^`(t, 6)), `*`(12, `*`(`^`(t, 4))), `*`(129, `*`(`^`(t, 2))), `-`(98)), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2)))))) (7.5)
 

`+`(jay, `-`(invariant)) = `+`(`-`(`/`(`*`(16, `*`(`^`(`+`(`-`(5), `*`(`^`(t, 2))), 6))), `*`(`+`(`*`(`^`(t, 6)), `*`(12, `*`(`^`(t, 4))), `*`(129, `*`(`^`(t, 2))), `-`(98)), `*`(`^`(`+`(`*`(`^`(t, 2)... (7.5)
 

`
` (7.5)
 

This is a rational elliptic surface; Oguiso-Shioda type No.7. (7.5)
 

`
` (7.5)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (7.5)
 

`
` (7.5)
 

The rank of the Mordell-Weil group over C is 5. (7.5)
 

` ` (7.5)
 

Type No.8 

 

>
 

> qc[8]:=x^3*y-x^2*z^2+y^2*z^2;
 

`:=`(qc[8], `+`(`*`(`^`(x, 3), `*`(y)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))), `*`(`^`(y, 2), `*`(`^`(z, 2))))) (8.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[8]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[8]),x,y);
 

{[[0, 1, 0], 2, 1, 1], [[0, 0, 1], 2, 1, 2]} (8.2)
 

> subs(y=t*x+z,qc[8]);
 

`+`(`*`(`^`(x, 3), `*`(`+`(`*`(t, `*`(x)), z))), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))), `*`(`^`(`+`(`*`(t, `*`(x)), z), 2), `*`(`^`(z, 2)))) (8.3)
 

> Q8:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q8, `+`(`*`(2, `*`(t, `*`(U))), `*`(`^`(U, 3)), `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`^`(U, 2)))), `*`(`^`(U, 4), `*`(t)), 1)) (8.4)
 

> subs(U=0,Q8);
simplify(%);
 

1 (8.5)
 

1 (8.5)
 

> Quartic_to_Weierstrass(Q8,[0,1]);
 

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

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

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

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `*`(2, `*`(t, `*`(X, `*`(`^`(Z, 2))))), `-`(`*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`^`(X, 2), `*`(Z))))), `-`(`*`(`+`(1, `*`(4, `*`(t))), `*`(`^`(Z, 3)... (8.8)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (8.9)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`^`(x, 2)))), `-`(`*`(2, `*`(t, `*`(x)))), 1, `*`(4, `*`(t))) (8.9)
 

> Show_data();
 

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

Discriminant = `+`(`-`(368), `-`(`*`(2624, `*`(t))), `-`(`*`(2240, `*`(`^`(t, 4)))), `-`(`*`(832, `*`(`^`(t, 3)))), `*`(768, `*`(`^`(t, 5))), `-`(`*`(4736, `*`(`^`(t, 2)))), `-`(`*`(256, `*`(`^`(t, 7)... (8.10)
 

`+`(jay, `-`(invariant)) = `+`(`-`(`/`(`*`(256, `*`(`^`(`+`(`*`(`^`(t, 4)), `-`(`*`(2, `*`(`^`(t, 2)))), 1, `*`(6, `*`(t))), 3))), `*`(`+`(23, `*`(164, `*`(t)), `*`(140, `*`(`^`(t, 4))), `*`(52, `*`(`... (8.10)
 

`
` (8.10)
 

This is a rational elliptic surface; Oguiso-Shioda type No.8. (8.10)
 

`
` (8.10)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi(
Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi(
(8.10)
 

`
` (8.10)
 

The rank of the Mordell-Weil group over C is 4. (8.10)
 

` ` (8.10)
 

Type No.9 

> qc[9]:=x^4+y^4-x^2*z^2;
 

`:=`(qc[9], `+`(`*`(`^`(x, 4)), `*`(`^`(y, 4)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))))) (9.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[9]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[9]),x,y);
 

{[[0, 0, 1], 2, 2, 2]} (9.2)
 

> subs(y=t*x+z,qc[9]);
 

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

> Q9:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q9, `+`(`*`(4, `*`(t, `*`(U))), `*`(4, `*`(`^`(t, 3), `*`(`^`(U, 3)))), `*`(`+`(`-`(1), `*`(6, `*`(`^`(t, 2)))), `*`(`^`(U, 2))), `*`(`+`(1, `*`(`^`(t, 4))), `*`(`^`(U, 4))), 1)) (9.4)
 

> subs(U=0,Q9);
simplify(%);
 

1 (9.5)
 

1 (9.5)
 

> Quartic_to_Weierstrass(Q9,[0,1]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(4, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(8, `*`(`^`(t, 3), `*`(Y, `*`(`^`(Z, 2))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(1), `*`(2, `*`(`^`(t, 2)))), `*`(`^`(X, 2), `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(4, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(8, `*`(`^`(t, 3), `*`(Y, `*`(`^`(Z, 2))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(1), `*`(2, `*`(`^`(t, 2)))), `*`(`^`(X, 2), `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(4, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(8, `*`(`^`(t, 3), `*`(Y, `*`(`^`(Z, 2))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(1), `*`(2, `*`(`^`(t, 2)))), `*`(`^`(X, 2), `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(4, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(8, `*`(`^`(t, 3), `*`(Y, `*`(`^`(Z, 2))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(1), `*`(2, `*`(`^`(t, 2)))), `*`(`^`(X, 2), `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(4, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(8, `*`(`^`(t, 3), `*`(Y, `*`(`^`(Z, 2))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(1), `*`(2, `*`(`^`(t, 2)))), `*`(`^`(X, 2), `*`...
(9.6)
 

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

`+`(`-`(`*`(`^`(X, 3))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(`+`(`*`(2, `*`(`^`(t, 6))), 1, `*`(`^`(t, 4)), `-`(`*`(2, `*`(`^`(t, 2))))), `*`(`^`(Z, 3))))), `-`(`*`(4, `*`(`+`(`*`(3, `*`(`^`(t, 4))...
`+`(`-`(`*`(`^`(X, 3))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(`+`(`*`(2, `*`(`^`(t, 6))), 1, `*`(`^`(t, 4)), `-`(`*`(2, `*`(`^`(t, 2))))), `*`(`^`(Z, 3))))), `-`(`*`(4, `*`(`+`(`*`(3, `*`(`^`(t, 4))...
(9.7)
 

`
     The curve you have entered is:` (9.7)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(1), `*`(6, `*`(`^`(t, 2)))), `*`(`^`(x, 2))), `*`(`+`(`*`(12, `*`(`^`(t, 4))), `-`(4)), `*`(x)), `-`(`*`(8, `*`(`^`(t, 2)))), `*`(8, `*`(`^`(t, 6))), 4... (9.7)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(1), `*`(6, `*`(`^`(t, 2)))), `*`(`^`(x, 2))), `*`(`+`(`*`(12, `*`(`^`(t, 4))), `-`(4)), `*`(x)), `-`(`*`(8, `*`(`^`(t, 2)))), `*`(8, `*`(`^`(t, 6))), 4... (9.8)
 

Discriminant = `+`(`-`(`*`(4096, `*`(`^`(t, 6)))), `*`(12544, `*`(`^`(t, 4))), `-`(`*`(17408, `*`(`^`(t, 2)))), 2304) (9.8)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(16, `*`(`^`(`+`(`-`(13), `*`(12, `*`(`^`(t, 2)))), 3))), `*`(`+`(`-`(9), `*`(68, `*`(`^`(t, 2))), `-`(`*`(49, `*`(`^`(t, 4)))), `*`(16, `*`(`^`(t, 6))))))) (9.8)
 

`
` (9.8)
 

This is a rational elliptic surface; Oguiso-Shioda type No.9. (9.8)
 

`
` (9.8)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (9.8)
 

`
` (9.8)
 

The rank of the Mordell-Weil group over C is 4. (9.8)
 

` ` (9.8)
 

Type No.10 

> qc[10]:=x^4+y^4+x^3*y-x^2*z^2;
 

`:=`(qc[10], `+`(`*`(`^`(x, 4)), `*`(`^`(y, 4)), `*`(`^`(x, 3), `*`(y)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))))) (10.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[10]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[10]),x,y);
 

{[[0, 0, 1], 2, 2, 2]} (10.2)
 

> subs(y=t*(x-z),qc[10]);
 

`+`(`*`(`^`(x, 4)), `*`(`^`(t, 4), `*`(`^`(`+`(x, `-`(z)), 4))), `*`(`^`(x, 3), `*`(t, `*`(`+`(x, `-`(z))))), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2))))) (10.3)
 

> Q10:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q10, `+`(`-`(`*`(4, `*`(`^`(t, 4), `*`(U)))), `*`(`+`(`*`(6, `*`(`^`(t, 4))), `-`(1)), `*`(`^`(U, 2))), `*`(`+`(`*`(`^`(t, 4)), 1, t), `*`(`^`(U, 4))), `-`(`*`(t, `*`(`+`(`*`(4, `*`(`^`(t, 3))), ... (10.4)
 

> subs(U=1,Q10);
simplify(%);
 

`+`(`*`(4, `*`(`^`(t, 4))), t, `-`(`*`(t, `*`(`+`(`*`(4, `*`(`^`(t, 3))), 1))))) (10.5)
 

0 (10.5)
 

> Quartic_to_Weierstrass(Q10,[1,0]);
 

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(5, `*`(3, `*`(t))), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`+`(4, `*`(3, `*`(t))), `*`(`+`(2, t), `*`(X, `*`(`^`(Z, 2)))))), `-`(`*`(`+`(`*`(`^`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(5, `*`(3, `*`(t))), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`+`(4, `*`(3, `*`(t))), `*`(`+`(2, t), `*`(X, `*`(`^`(Z, 2)))))), `-`(`*`(`+`(`*`(`^`...
(10.8)
 

 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (10.9)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(5, `*`(3, `*`(t))), `*`(`^`(x, 2))), `*`(`+`(4, `*`(3, `*`(t))), `*`(`+`(2, t), `*`(x))), `*`(`+`(`*`(`^`(t, 4)), 1, t), `*`(`^`(`+`(2, t), 2)))) (10.9)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(5, `*`(3, `*`(t))), `*`(`^`(x, 2))), `*`(`+`(4, `*`(3, `*`(t))), `*`(`+`(2, t), `*`(x))), `*`(`+`(`*`(`^`(t, 4)), 1, t), `*`(`^`(`+`(2, t), 2)))) (10.10)
 

Discriminant = `+`(`-`(`*`(16, `*`(`^`(t, 4), `*`(`+`(`*`(27, `*`(`^`(t, 6))), `*`(108, `*`(`^`(t, 5))), `*`(108, `*`(`^`(t, 4))), `-`(4)), `*`(`^`(`+`(2, t), 2))))))) (10.10)
 

`+`(jay, `-`(invariant)) = `+`(`-`(`/`(`*`(256), `*`(`^`(t, 4), `*`(`+`(`*`(27, `*`(`^`(t, 6))), `*`(108, `*`(`^`(t, 5))), `*`(108, `*`(`^`(t, 4))), `-`(4)), `*`(`^`(`+`(2, t), 2))))))) (10.10)
 

`
` (10.10)
 

This is a rational elliptic surface; Oguiso-Shioda type No.10. (10.10)
 

`
` (10.10)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (10.10)
 

`
` (10.10)
 

The rank of the Mordell-Weil group over C is 4. (10.10)
 

` ` (10.10)