Type31-40.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.31 

> qc[31]:=x^4+x^3*z-y^2*z^2;
 

`:=`(qc[31], `+`(`*`(`^`(x, 4)), `*`(`^`(x, 3), `*`(z)), `-`(`*`(`^`(y, 2), `*`(`^`(z, 2)))))) (1.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[31]),x,y);
 

Warning, the name changecoords has been redefined
 

Plot_2d
 

> singularities(subs(z=1,qc[31]),x,y);
 

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

> subs(y=t*(x+z)+z,qc[31]);
 

`+`(`*`(`^`(x, 4)), `*`(`^`(x, 3), `*`(z)), `-`(`*`(`^`(`+`(`*`(t, `*`(`+`(x, z))), z), 2), `*`(`^`(z, 2))))) (1.3)
 

> Q31:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q31, `+`(`-`(`*`(2, `*`(t, `*`(`+`(1, t), `*`(U))))), `*`(`^`(U, 4)), `*`(`^`(U, 3)), `-`(`*`(`^`(t, 2), `*`(`^`(U, 2)))), `-`(`*`(`^`(`+`(1, t), 2))))) (1.4)
 

> subs(U=-1,Q31);
simplify(%);
 

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

-1 (1.5)
 

> Quartic_to_Weierstrass(Q31,[-1,I]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`-`(`*`(2, `*`(t))), `-`(1)), `*`(X, `*`(Y, `*`(Z)))), `-`(`*`(6, `*`(Y, `*`(`^`(Z, 2))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`/`(13, 4)), `-`(t)), `*`(`^`(X, 2)...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`-`(`*`(2, `*`(t))), `-`(1)), `*`(X, `*`(Y, `*`(Z)))), `-`(`*`(6, `*`(Y, `*`(`^`(Z, 2))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`/`(13, 4)), `-`(t)), `*`(`^`(X, 2)...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`-`(`*`(2, `*`(t))), `-`(1)), `*`(X, `*`(Y, `*`(Z)))), `-`(`*`(6, `*`(Y, `*`(`^`(Z, 2))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`/`(13, 4)), `-`(t)), `*`(`^`(X, 2)...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`-`(`*`(2, `*`(t))), `-`(1)), `*`(X, `*`(Y, `*`(Z)))), `-`(`*`(6, `*`(Y, `*`(`^`(Z, 2))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`/`(13, 4)), `-`(t)), `*`(`^`(X, 2)...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`-`(`*`(2, `*`(t))), `-`(1)), `*`(X, `*`(Y, `*`(Z)))), `-`(`*`(6, `*`(Y, `*`(`^`(Z, 2))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`/`(13, 4)), `-`(t)), `*`(`^`(X, 2)...
(1.6)
 

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`+`(`*`(`^`(t, 2)), `-`(3)), `*`(`^`(X, 2), `*`(Z))))), `-`(`*`(16, `*`(`+`(`*`(6, `*`(t)), 7), `*`(X, `*`(`^`(Z, 2)))))), `*`(256, `*`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`+`(`*`(`^`(t, 2)), `-`(3)), `*`(`^`(X, 2), `*`(Z))))), `-`(`*`(16, `*`(`+`(`*`(6, `*`(t)), 7), `*`(X, `*`(`^`(Z, 2)))))), `*`(256, `*`(...
(1.7)
 

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(`^`(t, 2)), `-`(3)), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`+`(`*`(6, `*`(t)), 7), `*`(X, `*`(`^`(Z, 2))))), `*`(4, `*`(`+`(1, t), `*`(`^`(... (1.8)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (1.9)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(`^`(t, 2)), `-`(3)), `*`(`^`(x, 2))), `*`(`+`(`*`(6, `*`(t)), 7), `*`(x)), `-`(4), `-`(`*`(4, `*`(t)))) (1.9)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(`^`(t, 2)), `-`(3)), `*`(`^`(x, 2))), `*`(`+`(`*`(6, `*`(t)), 7), `*`(x)), `-`(4), `-`(`*`(4, `*`(t)))) (1.10)
 

Discriminant = `+`(`*`(16, `*`(`+`(`*`(16, `*`(`^`(t, 4))), `*`(4, `*`(`^`(t, 3))), `-`(`*`(120, `*`(`^`(t, 2)))), `-`(`*`(411, `*`(t))), `-`(283)), `*`(`^`(`+`(1, t), 3))))) (1.10)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(256, `*`(`^`(`+`(`-`(12), `-`(`*`(6, `*`(`^`(t, 2)))), `*`(`^`(t, 4)), `-`(`*`(18, `*`(t)))), 3))), `*`(`+`(`*`(16, `*`(`^`(t, 4))), `*`(4, `*`(`^`(t, 3))), `-`(... (1.10)
 

`
` (1.10)
 

This is a rational elliptic surface; Oguiso-Shioda type No.31. (1.10)
 

`
` (1.10)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (1.10)
 

`
` (1.10)
 

The rank of the Mordell-Weil group over C is 2. (1.10)
 

` ` (1.10)
 

> latex(y^2 = x^3+(t^2-3)*x^2+(6*t+7)*x-4-4*t);
 

{y}^{2}={x}^{3}+ \left( {t}^{2}-3 \right) {x}^{2}+ \left( 6\,t+7
 

\right) x-4-4\,t
 

TypeNo.32 

> qc[32]:=x^4+x^3*z-y^2*z^2;
 

`:=`(qc[32], `+`(`*`(`^`(x, 4)), `*`(`^`(x, 3), `*`(z)), `-`(`*`(`^`(y, 2), `*`(`^`(z, 2)))))) (2.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[32]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[32]),x,y);
 

{[[0, 0, 1], 2, 1, 1], [[0, 1, 0], 2, 2, 2]} (2.2)
 

> subs(z=t*(x-y),qc[32]);
 

`+`(`*`(`^`(x, 4)), `*`(`^`(x, 3), `*`(t, `*`(`+`(x, `-`(y))))), `-`(`*`(`^`(y, 2), `*`(`^`(t, 2), `*`(`^`(`+`(x, `-`(y)), 2)))))) (2.3)
 

> Q32:=mapfactor(subs({y=1,x=U},%),U);
 

`:=`(Q32, `+`(`*`(2, `*`(`^`(t, 2), `*`(U))), `*`(`+`(t, 1), `*`(`^`(U, 4))), `-`(`*`(`^`(t, 2), `*`(`^`(U, 2)))), `-`(`*`(`^`(U, 3), `*`(t))), `-`(`*`(`^`(t, 2))))) (2.4)
 

> subs(U=1,Q32);
simplify(%);
 

1 (2.5)
 

1 (2.5)
 

> Quartic_to_Weierstrass(Q32,[1,1]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(t, 4), `*`(X, `*`(Y, `*`(Z)))), `*`(`+`(`*`(6, `*`(t)), 8), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(`/`(5, 4), `*`(`*`(`^`(t, 2))))), t, 2...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(t, 4), `*`(X, `*`(Y, `*`(Z)))), `*`(`+`(`*`(6, `*`(t)), 8), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(`/`(5, 4), `*`(`*`(`^`(t, 2))))), t, 2...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(t, 4), `*`(X, `*`(Y, `*`(Z)))), `*`(`+`(`*`(6, `*`(t)), 8), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(`/`(5, 4), `*`(`*`(`^`(t, 2))))), t, 2...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(t, 4), `*`(X, `*`(Y, `*`(Z)))), `*`(`+`(`*`(6, `*`(t)), 8), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(`/`(5, 4), `*`(`*`(`^`(t, 2))))), t, 2...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(t, 4), `*`(X, `*`(Y, `*`(Z)))), `*`(`+`(`*`(6, `*`(t)), 8), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(`/`(5, 4), `*`(`*`(`^`(t, 2))))), t, 2...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(t, 4), `*`(X, `*`(Y, `*`(Z)))), `*`(`+`(`*`(6, `*`(t)), 8), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(`/`(5, 4), `*`(`*`(`^`(t, 2))))), t, 2...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(t, 4), `*`(X, `*`(Y, `*`(Z)))), `*`(`+`(`*`(6, `*`(t)), 8), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(`/`(5, 4), `*`(`*`(`^`(t, 2))))), t, 2...
(2.6)
 

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(64, `*`(`+`(8, `*`(5, `*`(`^`(t, 3))), `*`(10, `*`(`^`(t, 2))), `*`(12, `*`(t))), `*`(`^`(Z, 3))))), `*`(4, `*`(`+`(`-`(6), `-`(`*`(3, `*`(t)))...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(64, `*`(`+`(8, `*`(5, `*`(`^`(t, 3))), `*`(10, `*`(`^`(t, 2))), `*`(12, `*`(t))), `*`(`^`(Z, 3))))), `*`(4, `*`(`+`(`-`(6), `-`(`*`(3, `*`(t)))...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(64, `*`(`+`(8, `*`(5, `*`(`^`(t, 3))), `*`(10, `*`(`^`(t, 2))), `*`(12, `*`(t))), `*`(`^`(Z, 3))))), `*`(4, `*`(`+`(`-`(6), `-`(`*`(3, `*`(t)))...
(2.7)
 

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(8, `*`(5, `*`(`^`(t, 3))), `*`(10, `*`(`^`(t, 2))), `*`(12, `*`(t))), `*`(`^`(Z, 3)))), `*`(`+`(`-`(6), `-`(`*`(3, `*`(t))), `*`(`^`(t, 2))... (2.8)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (2.9)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(`*`(`^`(t, 2))), `*`(3, `*`(t)), 6), `*`(`^`(x, 2))), `*`(3, `*`(`^`(`+`(t, 2), 2), `*`(x))), 8, `*`(5, `*`(`^`(t, 3))), `*`(10, `*`(`^`(t, 2))), `*`(1... (2.9)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(`*`(`^`(t, 2))), `*`(3, `*`(t)), 6), `*`(`^`(x, 2))), `*`(3, `*`(`^`(`+`(t, 2), 2), `*`(x))), 8, `*`(5, `*`(`^`(t, 3))), `*`(10, `*`(`^`(t, 2))), `*`(1... (2.10)
 

Discriminant = `+`(`*`(16, `*`(`^`(t, 6), `*`(`+`(`-`(256), `-`(`*`(131, `*`(`^`(t, 2)))), `-`(`*`(384, `*`(t))), `*`(20, `*`(`^`(t, 3)))))))) (2.10)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(256, `*`(`^`(`+`(`-`(12), `*`(`^`(t, 2)), `-`(`*`(6, `*`(t)))), 3))), `*`(`+`(`-`(256), `-`(`*`(131, `*`(`^`(t, 2)))), `-`(`*`(384, `*`(t))), `*`(20, `*`(`^`(t, ... (2.10)
 

`
` (2.10)
 

This is a rational elliptic surface; Oguiso-Shioda type No.29. (2.10)
 

`
` (2.10)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (2.10)
 

`
` (2.10)
 

The rank of the Mordell-Weil group over C is 2. (2.10)
 

` ` (2.10)
 

TypeNo.33 

 

> qc[33]:=-y^2*(3*x^2-(3*z-y)^2)+x^3*(9*x+2*y-12*z);
 

`:=`(qc[33], `+`(`-`(`*`(`^`(y, 2), `*`(`+`(`*`(3, `*`(`^`(x, 2))), `-`(`*`(`^`(`+`(`*`(3, `*`(z)), `-`(y)), 2))))))), `*`(`^`(x, 3), `*`(`+`(`*`(9, `*`(x)), `*`(2, `*`(y)), `-`(`*`(12, `*`(z)))))))) (3.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[33]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[33]),x,y);
 

{[[1, 1, 1], 2, 1, 2], [[0, 0, 1], 2, 1, 1], [[0, 3, 1], 2, 1, 2]} (3.2)
 

> subs(y=t*x+6*z,qc[33]);
 

`+`(`-`(`*`(`^`(`+`(`*`(t, `*`(x)), `*`(6, `*`(z))), 2), `*`(`+`(`*`(3, `*`(`^`(x, 2))), `-`(`*`(`^`(`+`(`-`(`*`(3, `*`(z))), `-`(`*`(t, `*`(x)))), 2))))))), `*`(`^`(x, 3), `*`(`+`(`*`(9, `*`(x)), `*`... (3.3)
 

> Q33:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q33, `+`(`*`(324, `*`(t, `*`(U))), `*`(`+`(`-`(`*`(3, `*`(`^`(t, 2)))), `*`(`^`(t, 4)), `*`(2, `*`(t)), 9), `*`(`^`(U, 4))), `*`(18, `*`(t, `*`(`+`(`*`(`^`(t, 2)), `-`(2)), `*`(`^`(U, 3))))), `*`...
`:=`(Q33, `+`(`*`(324, `*`(t, `*`(U))), `*`(`+`(`-`(`*`(3, `*`(`^`(t, 2)))), `*`(`^`(t, 4)), `*`(2, `*`(t)), 9), `*`(`^`(U, 4))), `*`(18, `*`(t, `*`(`+`(`*`(`^`(t, 2)), `-`(2)), `*`(`^`(U, 3))))), `*`...
(3.4)
 

> subs(U=0,Q33);
simplify(%);
 

324 (3.5)
 

324 (3.5)
 

> Quartic_to_Weierstrass(Q33,[0,18]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(324, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(3779136, `*`(t, `*`(`+`(`*`(`^`(t, 2)), `-`(2)), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(11664, `*`(`^...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(324, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(3779136, `*`(t, `*`(`+`(`*`(`^`(t, 2)), `-`(2)), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(11664, `*`(`^...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(324, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(3779136, `*`(t, `*`(`+`(`*`(`^`(t, 2)), `-`(2)), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(11664, `*`(`^...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(324, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(3779136, `*`(t, `*`(`+`(`*`(`^`(t, 2)), `-`(2)), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(11664, `*`(`^...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(324, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(3779136, `*`(t, `*`(`+`(`*`(`^`(t, 2)), `-`(2)), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(11664, `*`(`^...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(324, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(3779136, `*`(t, `*`(`+`(`*`(`^`(t, 2)), `-`(2)), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(11664, `*`(`^...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(324, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(3779136, `*`(t, `*`(`+`(`*`(`^`(t, 2)), `-`(2)), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(11664, `*`(`^...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(324, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(3779136, `*`(t, `*`(`+`(`*`(`^`(t, 2)), `-`(2)), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(11664, `*`(`^...
(3.6)
 

`+`(`*`(`^`(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), `...
(3.7)
 

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(2916, `*`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(12)), `*`(`^`(X, 2), `*`(Z))))), `-`(`*`(68024448, `*`(`+`(`-`(18), `-`(`*`(12, `*`(`^`(t, 2)))), `*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(2916, `*`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(12)), `*`(`^`(X, 2), `*`(Z))))), `-`(`*`(68024448, `*`(`+`(`-`(18), `-`(`*`(12, `*`(`^`(t, 2)))), `*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(2916, `*`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(12)), `*`(`^`(X, 2), `*`(Z))))), `-`(`*`(68024448, `*`(`+`(`-`(18), `-`(`*`(12, `*`(`^`(t, 2)))), `*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(2916, `*`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(12)), `*`(`^`(X, 2), `*`(Z))))), `-`(`*`(68024448, `*`(`+`(`-`(18), `-`(`*`(12, `*`(`^`(t, 2)))), `*...
(3.8)
 

> mapfactor(subs({X=4*9*X,Y=8*27*Y},%[1])/(64*729),[X,Y]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(81, `*`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(12)), `*`(`^`(X, 2), `*`(Z))))), `-`(`*`(52488, `*`(`+`(`-`(18), `-`(`*`(12, `*`(`^`(t, 2)))), `*`(7, ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(81, `*`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(12)), `*`(`^`(X, 2), `*`(Z))))), `-`(`*`(52488, `*`(`+`(`-`(18), `-`(`*`(12, `*`(`^`(t, 2)))), `*`(7, ...
(3.9)
 

> mapfactor(subs({X=9*X,Y=27*Y},%)/729,[X,Y]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(9, `*`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(12)), `*`(`^`(X, 2), `*`(Z))))), `-`(`*`(648, `*`(`+`(`-`(18), `-`(`*`(12, `*`(`^`(t, 2)))), `*`(7, `*`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(9, `*`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(12)), `*`(`^`(X, 2), `*`(Z))))), `-`(`*`(648, `*`(`+`(`-`(18), `-`(`*`(12, `*`(`^`(t, 2)))), `*`(7, `*`...
(3.10)
 

> mapfactor(subs({X=9*X,Y=27*Y},%)/729,[X,Y]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(12)), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(8, `*`(`+`(`-`(18), `-`(`*`(12, `*`(`^`(t, 2)))), `*`(7, `*`(`^`(t, 4)...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(12)), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(8, `*`(`+`(`-`(18), `-`(`*`(12, `*`(`^`(t, 2)))), `*`(7, `*`(`^`(t, 4)...
(3.11)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (3.12)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(12)), `*`(`^`(x, 2))), `*`(`+`(`-`(144), `-`(`*`(96, `*`(`^`(t, 2)))), `*`(56, `*`(`^`(t, 4))), `-`(`*`(32, `*`(t)))), `*`(x))...
`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(12)), `*`(`^`(x, 2))), `*`(`+`(`-`(144), `-`(`*`(96, `*`(`^`(t, 2)))), `*`(56, `*`(`^`(t, 4))), `-`(`*`(32, `*`(t)))), `*`(x))...
(3.12)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(12)), `*`(`^`(x, 2))), `*`(`+`(`-`(144), `-`(`*`(96, `*`(`^`(t, 2)))), `*`(56, `*`(`^`(t, 4))), `-`(`*`(32, `*`(t)))), `*`(x))...
`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(13, `*`(`^`(t, 2))), `-`(12)), `*`(`^`(x, 2))), `*`(`+`(`-`(144), `-`(`*`(96, `*`(`^`(t, 2)))), `*`(56, `*`(`^`(t, 4))), `-`(`*`(32, `*`(t)))), `*`(x))...
(3.13)
 

Discriminant = `+`(`-`(`*`(4096, `*`(`^`(t, 2), `*`(`+`(`*`(2, `*`(t)), 9), `*`(`+`(`*`(3, `*`(`^`(t, 2))), `-`(`*`(32, `*`(t))), 128), `*`(`^`(`+`(t, 5), 2)))))))) (3.13)
 

`+`(jay, `-`(invariant)) = `+`(`-`(`/`(`*`(`^`(`+`(576, `-`(`*`(24, `*`(`^`(t, 2)))), `*`(`^`(t, 4)), `*`(96, `*`(t))), 3)), `*`(`^`(t, 2), `*`(`+`(`*`(2, `*`(t)), 9), `*`(`+`(`*`(3, `*`(`^`(t, 2))), ... (3.13)
 

`
` (3.13)
 

This is a rational elliptic surface; Oguiso-Shioda type No.33. (3.13)
 

`
` (3.13)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (3.13)
 

`
` (3.13)
 

The rank of the Mordell-Weil group over C is 2. (3.13)
 

` ` (3.13)
 

TypeNo.34 

> qc[34]:=x^4+y^4-x^2*z^2;
 

`:=`(qc[34], `+`(`*`(`^`(x, 4)), `*`(`^`(y, 4)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))))) (4.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[34]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[34]),x,y);
 

{[[0, 0, 1], 2, 2, 2]} (4.2)
 

> subs(z=t*x,qc[34]);
 

`+`(`*`(`^`(x, 4)), `*`(`^`(y, 4)), `-`(`*`(`^`(x, 4), `*`(`^`(t, 2))))) (4.3)
 

> Q34:=mapfactor(subs({y=1,x=U},%),U);
 

`:=`(Q34, `+`(`-`(`*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`^`(U, 4))))), 1)) (4.4)
 

> subs(U=0,Q34);
simplify(%);
 

1 (4.5)
 

1 (4.5)
 

> Quartic_to_Weierstrass(Q34,[0,1]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(X, `*`(`^`(Z, 2)))))))), {X = `+`(`*`(2, `*`(`+`(V, 1), `*`(U)))), Y = `+`(`*`(4, `*`(V)), 4), Z = `*...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(X, `*`(`^`(Z, 2)))))))), {X = `+`(`*`(2, `*`(`+`(V, 1), `*`(U)))), Y = `+`(`*`(4, `*`(V)), 4), Z = `*...
(4.6)
 

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(X, `*`(`^`(Z, 2)))))))), {x = X, y = Y, z = Z}, [x, y, z] (4.7)
 

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

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

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (4.9)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(4, `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(x))))) (4.9)
 

> Show_data();
 

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

Discriminant = `+`(`-`(`*`(4096, `*`(`^`(`+`(t, `-`(1)), 3), `*`(`^`(`+`(t, 1), 3)))))) (4.10)
 

`+`(jay, `-`(invariant)) = 1728 (4.10)
 

`
` (4.10)
 

This is a rational elliptic surface; Oguiso-Shioda type No.34. (4.10)
 

`
` (4.10)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (4.10)
 

`
` (4.10)
 

The rank of the Mordell-Weil group over C is 2. (4.10)
 

 

TypeNo.35 

> qc[35]:=(x^2+y^2-z^2)*(2*x^2+y^2-2*z^2);
 

`:=`(qc[35], `*`(`+`(`*`(`^`(x, 2)), `*`(`^`(y, 2)), `-`(`*`(`^`(z, 2)))), `*`(`+`(`*`(2, `*`(`^`(x, 2))), `*`(`^`(y, 2)), `-`(`*`(2, `*`(`^`(z, 2)))))))) (5.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[35]),x,y);
 

Warning, the name changecoords has been redefined
 

Plot_2d
 

> singularities(subs(z=1,qc[35]),x,y);
 

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

> subs(y=t*x+2*z,qc[35]);
 

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

> Q35:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q35, `+`(`*`(20, `*`(t, `*`(U))), `*`(`+`(`*`(`^`(t, 2)), 2), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(`^`(U, 4)))), `*`(4, `*`(t, `*`(`+`(3, `*`(2, `*`(`^`(t, 2)))), `*`(`^`(U, 3))))), `*`(`+`(`*`(21, `*... (5.4)
 

> subs(U=0,Q35);
simplify(%);
 

6 (5.5)
 

6 (5.5)
 

> Quartic_to_Weierstrass(Q35,[0,6^(1/2)]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(20, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(288, `*`(t, `*`(`+`(3, `*`(2, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(26, `*`(`^`(t, ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(20, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(288, `*`(t, `*`(`+`(3, `*`(2, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(26, `*`(`^`(t, ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(20, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(288, `*`(t, `*`(`+`(3, `*`(2, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(26, `*`(`^`(t, ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(20, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(288, `*`(t, `*`(`+`(3, `*`(2, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(26, `*`(`^`(t, ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(20, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(288, `*`(t, `*`(`+`(3, `*`(2, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(26, `*`(`^`(t, ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(20, `*`(t, `*`(X, `*`(Y, `*`(Z))))), `*`(288, `*`(t, `*`(`+`(3, `*`(2, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`*`(26, `*`(`^`(t, ...
(5.6)
 

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

`+`(`-`(`*`(288, `*`(`+`(`*`(17, `*`(`^`(t, 4))), `*`(21, `*`(`^`(t, 2))), `-`(6)), `*`(X, `*`(`^`(Z, 2)))))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(1728, `*`(`+`(`*`(5, `*`(`^`(t, 2)))...
`+`(`-`(`*`(288, `*`(`+`(`*`(17, `*`(`^`(t, 4))), `*`(21, `*`(`^`(t, 2))), `-`(6)), `*`(X, `*`(`^`(Z, 2)))))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(1728, `*`(`+`(`*`(5, `*`(`^`(t, 2)))...
`+`(`-`(`*`(288, `*`(`+`(`*`(17, `*`(`^`(t, 4))), `*`(21, `*`(`^`(t, 2))), `-`(6)), `*`(X, `*`(`^`(Z, 2)))))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(1728, `*`(`+`(`*`(5, `*`(`^`(t, 2)))...
(5.7)
 

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

`+`(`-`(`*`(288, `*`(`+`(`*`(17, `*`(`^`(t, 4))), `*`(21, `*`(`^`(t, 2))), `-`(6)), `*`(X, `*`(`^`(Z, 2)))))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(1728, `*`(`+`(`*`(5, `*`(`^`(t, 2)))...
`+`(`-`(`*`(288, `*`(`+`(`*`(17, `*`(`^`(t, 4))), `*`(21, `*`(`^`(t, 2))), `-`(6)), `*`(X, `*`(`^`(Z, 2)))))), `*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(1728, `*`(`+`(`*`(5, `*`(`^`(t, 2)))...
(5.8)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (5.9)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(126, `*`(`^`(t, 2))), 48), `*`(`^`(x, 2))), `*`(`+`(`*`(4896, `*`(`^`(t, 4))), `*`(6048, `*`(`^`(t, 2))), `-`(1728)), `*`(x)), `*`(1728, `*`(`+`(`*`(5,...
`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(126, `*`(`^`(t, 2))), 48), `*`(`^`(x, 2))), `*`(`+`(`*`(4896, `*`(`^`(t, 4))), `*`(6048, `*`(`^`(t, 2))), `-`(1728)), `*`(x)), `*`(1728, `*`(`+`(`*`(5,...
(5.9)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(126, `*`(`^`(t, 2))), 48), `*`(`^`(x, 2))), `*`(`+`(`*`(4896, `*`(`^`(t, 4))), `*`(6048, `*`(`^`(t, 2))), `-`(1728)), `*`(x)), `*`(1728, `*`(`+`(`*`(5,...
`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`*`(126, `*`(`^`(t, 2))), 48), `*`(`^`(x, 2))), `*`(`+`(`*`(4896, `*`(`^`(t, 4))), `*`(6048, `*`(`^`(t, 2))), `-`(1728)), `*`(x)), `*`(1728, `*`(`+`(`*`(5,...
(5.10)
 

Discriminant = `+`(`*`(23887872, `*`(`+`(`*`(`^`(t, 2)), `-`(2)), `*`(`+`(`*`(`^`(t, 2)), `-`(3)), `*`(`^`(`+`(t, `-`(2)), 4), `*`(`^`(`+`(t, 2), 4))))))) (5.10)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(8, `*`(`^`(`+`(208, `-`(`*`(168, `*`(`^`(t, 2)))), `*`(33, `*`(`^`(t, 4)))), 3))), `*`(`+`(`*`(`^`(t, 2)), `-`(2)), `*`(`+`(`*`(`^`(t, 2)), `-`(3)), `*`(`^`(`+`(... (5.10)
 

`
` (5.10)
 

This is a rational elliptic surface; Oguiso-Shioda type No.35. (5.10)
 

`
` (5.10)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (5.10)
 

`
` (5.10)
 

The rank of the Mordell-Weil group over C is 2. (5.10)
 

` ` (5.10)
 

TypeNo.36 

> qc[36]:=x^4+x^3*z+y^2*z^2;
 

`:=`(qc[36], `+`(`*`(`^`(x, 4)), `*`(`^`(x, 3), `*`(z)), `*`(`^`(y, 2), `*`(`^`(z, 2))))) (6.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[36]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[36]),x,y);
 

{[[0, 0, 1], 2, 1, 1], [[0, 1, 0], 2, 2, 2]} (6.2)
 

> subs(z=t*(x-2*y)+2*y,qc[36]);
 

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

> Q36:=mapfactor(subs({y=1,x=U},%),U);
 

`:=`(Q36, `+`(`-`(`*`(4, `*`(t, `*`(`+`(t, `-`(1)), `*`(U))))), `*`(`+`(t, 1), `*`(`^`(U, 4))), `-`(`*`(2, `*`(`+`(t, `-`(1)), `*`(`^`(U, 3))))), `*`(`^`(t, 2), `*`(`^`(U, 2))), `*`(4, `*`(`^`(`+`(t, ... (6.4)
 

> subs(U=2,Q36);
simplify(%);
 

`+`(`-`(`*`(8, `*`(t, `*`(`+`(t, `-`(1)))))), 32, `*`(4, `*`(`^`(t, 2))), `*`(4, `*`(`^`(`+`(t, `-`(1)), 2)))) (6.5)
 

36 (6.5)
 

> Quartic_to_Weierstrass(Q36,[2,6]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`*`(12, `*`(t)), 56), `*`(Z, `*`(Y, `*`(X)))), `*`(`+`(25920, `*`(15552, `*`(t))), `*`(`^`(Z, 2), `*`(Y))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(512, `*`(96, `*`(t))), ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`*`(12, `*`(t)), 56), `*`(Z, `*`(Y, `*`(X)))), `*`(`+`(25920, `*`(15552, `*`(t))), `*`(`^`(Z, 2), `*`(Y))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(512, `*`(96, `*`(t))), ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`*`(12, `*`(t)), 56), `*`(Z, `*`(Y, `*`(X)))), `*`(`+`(25920, `*`(15552, `*`(t))), `*`(`^`(Z, 2), `*`(Y))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(512, `*`(96, `*`(t))), ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`*`(12, `*`(t)), 56), `*`(Z, `*`(Y, `*`(X)))), `*`(`+`(25920, `*`(15552, `*`(t))), `*`(`^`(Z, 2), `*`(Y))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(512, `*`(96, `*`(t))), ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`*`(12, `*`(t)), 56), `*`(Z, `*`(Y, `*`(X)))), `*`(`+`(25920, `*`(15552, `*`(t))), `*`(`^`(Z, 2), `*`(Y))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(512, `*`(96, `*`(t))), ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`*`(12, `*`(t)), 56), `*`(Z, `*`(Y, `*`(X)))), `*`(`+`(25920, `*`(15552, `*`(t))), `*`(`^`(Z, 2), `*`(Y))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(512, `*`(96, `*`(t))), ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `*`(`+`(`*`(12, `*`(t)), 56), `*`(Z, `*`(Y, `*`(X)))), `*`(`+`(25920, `*`(15552, `*`(t))), `*`(`^`(Z, 2), `*`(Y))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(512, `*`(96, `*`(t))), ...
(6.6)
 

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(746496, `*`(`+`(`*`(118, `*`(t)), `*`(57, `*`(`^`(t, 2))), 97), `*`(`^`(Z, 3))))), `-`(`*`(36, `*`(`^`(`+`(t, 6), 2), `*`(`^`(X, 2), `*`(Z)))))...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(746496, `*`(`+`(`*`(118, `*`(t)), `*`(57, `*`(`^`(t, 2))), 97), `*`(`^`(Z, 3))))), `-`(`*`(36, `*`(`^`(`+`(t, 6), 2), `*`(`^`(X, 2), `*`(Z)))))...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(746496, `*`(`+`(`*`(118, `*`(t)), `*`(57, `*`(`^`(t, 2))), 97), `*`(`^`(Z, 3))))), `-`(`*`(36, `*`(`^`(`+`(t, 6), 2), `*`(`^`(X, 2), `*`(Z)))))...
(6.7)
 

> mapfactor(subs({X=4*9*X,Y=8*27*Y},%[1])/(729*64),[X,Y]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(16, `*`(`+`(`*`(118, `*`(t)), `*`(57, `*`(`^`(t, 2))), 97), `*`(`^`(Z, 3))))), `-`(`*`(`^`(`+`(t, 6), 2), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(8, ... (6.8)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (6.9)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`^`(`+`(t, 6), 2), `*`(`^`(x, 2))), `*`(`+`(416, `*`(72, `*`(`^`(t, 2))), `*`(312, `*`(t))), `*`(x)), 1552, `*`(1888, `*`(t)), `*`(912, `*`(`^`(t, 2)))) (6.9)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`^`(`+`(t, 6), 2), `*`(`^`(x, 2))), `*`(`+`(416, `*`(72, `*`(`^`(t, 2))), `*`(312, `*`(t))), `*`(x)), 1552, `*`(1888, `*`(t)), `*`(912, `*`(`^`(t, 2)))) (6.10)
 

Discriminant = `+`(`*`(4096, `*`(`+`(`*`(6, `*`(`^`(t, 4))), `*`(143, `*`(`^`(t, 3))), `-`(`*`(260, `*`(`^`(t, 2)))), `*`(76, `*`(t)), 37), `*`(`^`(`+`(t, `-`(1)), 4))))) (6.10)
 

`+`(jay, `-`(invariant)) = `/`(`*`(`^`(`+`(`*`(`^`(t, 4)), `*`(24, `*`(`^`(t, 3))), `-`(`*`(72, `*`(t))), 48), 3)), `*`(`+`(`*`(6, `*`(`^`(t, 4))), `*`(143, `*`(`^`(t, 3))), `-`(`*`(260, `*`(`^`(t, 2)... (6.10)
 

`
` (6.10)
 

This is a rational elliptic surface; Oguiso-Shioda type No.36. (6.10)
 

`
` (6.10)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (6.10)
 

`
` (6.10)
 

The rank of the Mordell-Weil group over C is 2. (6.10)
 

` ` (6.10)
 

TypeNo.37 

> qc[37]:=x^4+x^3*z-2*y^2*z^2;
 

`:=`(qc[37], `+`(`*`(`^`(x, 4)), `*`(`^`(x, 3), `*`(z)), `-`(`*`(2, `*`(`^`(y, 2), `*`(`^`(z, 2))))))) (7.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[37]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[37]),x,y);
 

{[[0, 0, 1], 2, 1, 1], [[0, 1, 0], 2, 2, 2]} (7.2)
 

> subs(y=t*(x-z)+z,qc[37]);
 

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

> Q37:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q37, `+`(`*`(4, `*`(t, `*`(`+`(t, `-`(1)), `*`(U)))), `*`(`^`(U, 4)), `*`(`^`(U, 3)), `-`(`*`(2, `*`(`^`(t, 2), `*`(`^`(U, 2))))), `-`(`*`(2, `*`(`^`(`+`(t, `-`(1)), 2)))))) (7.4)
 

> subs(U=1,Q37);
simplify(%);
 

`+`(`*`(4, `*`(t, `*`(`+`(t, `-`(1))))), 2, `-`(`*`(2, `*`(`^`(t, 2)))), `-`(`*`(2, `*`(`^`(`+`(t, `-`(1)), 2))))) (7.5)
 

0 (7.5)
 

> Quartic_to_Weierstrass(Q37,[1,0]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(2, `*`(`^`(t, 2)))), 9), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`+`(35, `-`(`*`(20, `*`(t)))), `*`(X, `*`(`^`(Z, 2))))), `-`(`*`(`^`(`+`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(2, `*`(`^`(t, 2)))), 9), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`+`(35, `-`(`*`(20, `*`(t)))), `*`(X, `*`(`^`(Z, 2))))), `-`(`*`(`^`(`+`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(`-`(`*`(2, `*`(`^`(t, 2)))), 9), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(`+`(35, `-`(`*`(20, `*`(t)))), `*`(X, `*`(`^`(Z, 2))))), `-`(`*`(`^`(`+`...
(7.6)
 

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`^`(`+`(`*`(4, `*`(t)), `-`(7)), 2), `*`(`^`(Z, 3)))), `*`(`+`(`-`(9), `*`(2, `*`(`^`(t, 2)))), `*`(`^`(X, 2), `*`(Z))), `*`(5, `*`(`+`(`*`(4, ...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`^`(`+`(`*`(4, `*`(t)), `-`(7)), 2), `*`(`^`(Z, 3)))), `*`(`+`(`-`(9), `*`(2, `*`(`^`(t, 2)))), `*`(`^`(X, 2), `*`(Z))), `*`(5, `*`(`+`(`*`(4, ...
(7.7)
 

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`^`(`+`(`*`(4, `*`(t)), `-`(7)), 2), `*`(`^`(Z, 3)))), `*`(`+`(`-`(9), `*`(2, `*`(`^`(t, 2)))), `*`(`^`(X, 2), `*`(Z))), `*`(5, `*`(`+`(`*`(4, ... (7.8)
 

> Elliptic_surface(%);
 

`
     The curve you have entered is:` (7.9)
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(`*`(2, `*`(`^`(t, 2)))), 9), `*`(`^`(x, 2))), `*`(`+`(35, `-`(`*`(20, `*`(t)))), `*`(x)), `*`(`^`(`+`(`*`(4, `*`(t)), `-`(7)), 2))) (7.9)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(`-`(`*`(2, `*`(`^`(t, 2)))), 9), `*`(`^`(x, 2))), `*`(`+`(35, `-`(`*`(20, `*`(t)))), `*`(x)), `*`(`^`(`+`(`*`(4, `*`(t)), `-`(7)), 2))) (7.10)
 

Discriminant = `+`(`*`(64, `*`(`+`(11, `-`(`*`(35, `*`(t))), `*`(24, `*`(`^`(t, 2))), `*`(8, `*`(`^`(t, 3)))), `*`(`^`(`+`(`*`(4, `*`(t)), `-`(7)), 2), `*`(`^`(`+`(t, `-`(1)), 3)))))) (7.10)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(4096, `*`(`^`(`+`(`-`(6), `-`(`*`(9, `*`(`^`(t, 2)))), `*`(`^`(t, 4)), `*`(15, `*`(t))), 3))), `*`(`+`(11, `-`(`*`(35, `*`(t))), `*`(24, `*`(`^`(t, 2))), `*`(8, ... (7.10)
 

`
` (7.10)
 

This is a rational elliptic surface; Oguiso-Shioda type No.37. (7.10)
 

`
` (7.10)
 

Typesetting:-mrow(Typesetting:-mrow(Typesetting:-mi( (7.10)
 

`
` (7.10)
 

The rank of the Mordell-Weil group over C is 2. (7.10)
 

` ` (7.10)
 

TypeNo.38 

> qc[38]:=(x^2+y^2)^2-x^2*z^2+y^2*z^2;
 

`:=`(qc[38], `+`(`*`(`^`(`+`(`*`(`^`(x, 2)), `*`(`^`(y, 2))), 2)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))), `*`(`^`(y, 2), `*`(`^`(z, 2))))) (8.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[38]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[38]),x,y);
 

{[[0, 0, 1], 2, 1, 2], [[RootOf(`+`(`*`(`^`(_Z, 2)), 1)), 1, 0], 2, 1, 2]} (8.2)
 

> subs(z=t*x,qc[38]);
 

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

> Q38:=mapfactor(subs({y=1,x=U},%),U);
 

`:=`(Q38, `+`(`*`(`+`(2, `*`(`^`(t, 2))), `*`(`^`(U, 2))), `-`(`*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`^`(U, 4))))), 1)) (8.4)
 

> subs(U=0,Q38);
simplify(%);
 

1 (8.5)
 

1 (8.5)
 

> Quartic_to_Weierstrass(Q38,[0,1]);
 

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

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(2, `*`(`^`(t, 2))), `*`(`^`(X, 2), `*`(Z)))), `-`(`*`(4, `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(X, `*`(`^`(Z, 2))))))), `-`(`*`(4, `*`(`+`(... (8.9)
 

> Elliptic_surface(%);
 

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

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

> Show_data();
 

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

Discriminant = `+`(`-`(`*`(256, `*`(`^`(t, 4), `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`^`(`+`(`*`(`^`(t, 2)), 8), 2)))))))) (8.11)
 

`+`(jay, `-`(invariant)) = `+`(`-`(`/`(`*`(16, `*`(`^`(`+`(t, `-`(2)), 6), `*`(`^`(`+`(t, 2), 6)))), `*`(`^`(t, 4), `*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`^`(`+`(`*`(`^`(t, 2)), 8), 2)))))))) (8.11)
 

`
` (8.11)
 

This is a rational elliptic surface; Oguiso-Shioda type No.38. (8.11)
 

`
` (8.11)
 

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

`
` (8.11)
 

The rank of the Mordell-Weil group over C is 2. (8.11)
 

` ` (8.11)
 

TypeNo.39 

> qc[39]:=(x^2+y^2-x*z)^2-x^2*z^2-y^2*z^2;
 

`:=`(qc[39], `+`(`*`(`^`(`+`(`*`(`^`(x, 2)), `*`(`^`(y, 2)), `-`(`*`(x, `*`(z)))), 2)), `-`(`*`(`^`(x, 2), `*`(`^`(z, 2)))), `-`(`*`(`^`(y, 2), `*`(`^`(z, 2)))))) (9.1)
 

> with(plots):

with(algcurves):
plot_real_curve(subs(z=1,qc[39]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[39]),x,y);
 

{[[0, 0, 1], 2, 1, 1], [[RootOf(`+`(`*`(`^`(_Z, 2)), 1)), 1, 0], 2, 1, 1]} (9.2)
 

> subs(y=t*(x-z),qc[39]);
 

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

> Q39:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q39, `+`(`*`(`^`(t, 2), `*`(`+`(5, `*`(6, `*`(`^`(t, 2)))), `*`(`^`(U, 2)))), `-`(`*`(4, `*`(`^`(t, 4), `*`(U)))), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2), `*`(`^`(U, 4))), `-`(`*`(2, `*`(`+`(`*`(2, `...
`:=`(Q39, `+`(`*`(`^`(t, 2), `*`(`+`(5, `*`(6, `*`(`^`(t, 2)))), `*`(`^`(U, 2)))), `-`(`*`(4, `*`(`^`(t, 4), `*`(U)))), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2), `*`(`^`(U, 4))), `-`(`*`(2, `*`(`+`(`*`(2, `...
(9.4)
 

> subs(U=1,Q39);
simplify(%);
 

`+`(`*`(`^`(t, 2), `*`(`+`(5, `*`(6, `*`(`^`(t, 2)))))), `-`(`*`(4, `*`(`^`(t, 4)))), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2)), `-`(`*`(2, `*`(`+`(`*`(2, `*`(`^`(t, 2))), 1), `*`(`+`(`*`(`^`(t, 2)), 1)))))... (9.5)
 

-1 (9.5)
 

> Quartic_to_Weierstrass(Q39,[1,I]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(2, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(4, `*`(4, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`^`(X, 2),...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(2, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(4, `*`(4, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`^`(X, 2),...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(2, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(4, `*`(4, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`^`(X, 2),...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(2, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(4, `*`(4, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`^`(X, 2),...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(2, `*`(X, `*`(Y, `*`(Z))))), `*`(`+`(4, `*`(4, `*`(`^`(t, 2)))), `*`(Y, `*`(`^`(Z, 2)))), `-`(`*`(`^`(X, 3))), `-`(`*`(`+`(t, `-`(1)), `*`(`+`(t, 1), `*`(`^`(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)), `-`(`*`(4, `*`(`^`(t, 2), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(`^`(Z, 2))))))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`^`(t, 2), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2), `*`(`^`...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(4, `*`(`^`(t, 2), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(`^`(Z, 2))))))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`^`(t, 2), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2), `*`(`^`...
(9.8)
 

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

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

> Elliptic_surface(%);
 

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

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`^`(t, 2), `*`(`^`(x, 2))), `*`(4, `*`(`^`(t, 2), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(x)))), `*`(4, `*`(`^`(t, 2), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2))))) (9.10)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`^`(t, 2), `*`(`^`(x, 2))), `*`(4, `*`(`^`(t, 2), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(x)))), `*`(4, `*`(`^`(t, 2), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2))))) (9.11)
 

Discriminant = `+`(`-`(`*`(256, `*`(`^`(t, 4), `*`(`+`(`*`(25, `*`(`^`(t, 2))), 27), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 3))))))) (9.11)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(16, `*`(`^`(t, 2), `*`(`^`(`+`(`*`(11, `*`(`^`(t, 2))), 12), 3)))), `*`(`+`(`*`(25, `*`(`^`(t, 2))), 27), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 3))))) (9.11)
 

`
` (9.11)
 

This is a rational elliptic surface; Oguiso-Shioda type No.39. (9.11)
 

`
` (9.11)
 

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

`
` (9.11)
 

The rank of the Mordell-Weil group over C is 2. (9.11)
 

` ` (9.11)
 

TypeNo.40 

> qc[40]:=(x^2+y^2-2*x*z)^2-x^2*z^2-y^2*z^2;
 

`:=`(qc[40], `+`(`*`(`^`(`+`(`*`(`^`(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[40]),x,y);
 

Plot_2d
 

> singularities(subs(z=1,qc[40]),x,y);
 

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

> subs(y=t*x+z,qc[40]);
 

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

> Q40:=mapfactor(subs({z=1,x=U},%),U);
 

`:=`(Q40, `+`(`*`(`+`(5, `*`(5, `*`(`^`(t, 2))), `-`(`*`(8, `*`(t)))), `*`(`^`(U, 2))), `*`(2, `*`(`+`(t, `-`(2)), `*`(U))), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 2), `*`(`^`(U, 4))), `*`(4, `*`(`+`(t, `-`(... (10.4)
 

> subs(U=0,Q40);
simplify(%);
 

0 (10.5)
 

0 (10.5)
 

> Quartic_to_Weierstrass(Q40,[0,0]);
 

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(8, `*`(`+`(t, `-`(1)), `*`(`+`(t, `-`(2)), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(`^`(Z, 2)))))))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`^`(`+`(t, `-`(2)), 2), `*`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(8, `*`(`+`(t, `-`(1)), `*`(`+`(t, `-`(2)), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(`^`(Z, 2)))))))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`^`(`+`(t, `-`(2)), 2), `*`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(8, `*`(`+`(t, `-`(1)), `*`(`+`(t, `-`(2)), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(`^`(Z, 2)))))))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`^`(`+`(t, `-`(2)), 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)), `-`(`*`(8, `*`(`+`(t, `-`(1)), `*`(`+`(t, `-`(2)), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(`^`(Z, 2)))))))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`^`(`+`(t, `-`(2)), 2), `*`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(8, `*`(`+`(t, `-`(1)), `*`(`+`(t, `-`(2)), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(`^`(Z, 2)))))))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`^`(`+`(t, `-`(2)), 2), `*`(...
(10.8)
 

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

`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(8, `*`(`+`(t, `-`(1)), `*`(`+`(t, `-`(2)), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(`^`(Z, 2)))))))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`^`(`+`(t, `-`(2)), 2), `*`(...
`+`(`*`(`^`(Y, 2), `*`(Z)), `-`(`*`(8, `*`(`+`(t, `-`(1)), `*`(`+`(t, `-`(2)), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(X, `*`(`^`(Z, 2)))))))), `-`(`*`(`^`(X, 3))), `-`(`*`(4, `*`(`^`(`+`(t, `-`(2)), 2), `*`(...
(10.9)
 

> Elliptic_surface(%);
 

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

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(5, `*`(5, `*`(`^`(t, 2))), `-`(`*`(8, `*`(t)))), `*`(`^`(x, 2))), `*`(8, `*`(`+`(t, `-`(1)), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(`+`(t, `-`(2)), `*`(x))))), `*... (10.10)
 

> Show_data();
 

`*`(`^`(y, 2)) = `+`(`*`(`^`(x, 3)), `*`(`+`(5, `*`(5, `*`(`^`(t, 2))), `-`(`*`(8, `*`(t)))), `*`(`^`(x, 2))), `*`(8, `*`(`+`(t, `-`(1)), `*`(`+`(`*`(`^`(t, 2)), 1), `*`(`+`(t, `-`(2)), `*`(x))))), `*... (10.11)
 

Discriminant = `+`(`*`(256, `*`(`+`(`*`(3, `*`(`^`(t, 2))), `-`(`*`(32, `*`(t))), `-`(29)), `*`(`^`(`+`(t, `-`(2)), 2), `*`(`^`(`+`(`*`(`^`(t, 2)), 1), 3)))))) (10.11)
 

`+`(jay, `-`(invariant)) = `+`(`/`(`*`(16, `*`(`^`(`+`(`-`(23), `*`(42, `*`(`^`(t, 2))), `-`(`*`(8, `*`(t))), `*`(`^`(t, 4)), `-`(`*`(8, `*`(`^`(t, 3))))), 3))), `*`(`+`(`*`(3, `*`(`^`(t, 2))), `-`(`*... (10.11)
 

`
` (10.11)
 

This is a rational elliptic surface; Oguiso-Shioda type No.40. (10.11)
 

`
` (10.11)
 

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

`
` (10.11)
 

The rank of the Mordell-Weil group over C is 2. (10.11)
 

` ` (10.11)
 

>