Properties

Label 464.a.29696.1
Conductor $464$
Discriminant $-29696$
Mordell-Weil group \(\Z/{2}\Z \oplus \Z/{8}\Z\)
Sato-Tate group $\mathrm{USp}(4)$
\(\End(J_{\overline{\Q}}) \otimes \R\) \(\R\)
\(\End(J_{\overline{\Q}}) \otimes \Q\) \(\Q\)
\(\End(J) \otimes \Q\) \(\Q\)
\(\overline{\Q}\)-simple yes
\(\mathrm{GL}_2\)-type no

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Minimal equation

Minimal equation

Simplified equation

$y^2 + (x + 1)y = 8x^5 + 3x^4 - 4x^3 - 2x^2$ (homogenize, simplify)
$y^2 + (xz^2 + z^3)y = 8x^5z + 3x^4z^2 - 4x^3z^3 - 2x^2z^4$ (dehomogenize, simplify)
$y^2 = 32x^5 + 12x^4 - 16x^3 - 7x^2 + 2x + 1$ (homogenize, minimize)

sage: R.<x> = PolynomialRing(QQ); C = HyperellipticCurve(R([0, 0, -2, -4, 3, 8]), R([1, 1]));
 
magma: R<x> := PolynomialRing(Rationals()); C := HyperellipticCurve(R![0, 0, -2, -4, 3, 8], R![1, 1]);
 
sage: X = HyperellipticCurve(R([1, 2, -7, -16, 12, 32]))
 
magma: X,pi:= SimplifiedModel(C);
 

Invariants

Conductor: \( N \)  \(=\)  \(464\) \(=\) \( 2^{4} \cdot 29 \)
magma: Conductor(LSeries(C)); Factorization($1);
 
Discriminant: \( \Delta \)  \(=\)  \(-29696\) \(=\) \( - 2^{10} \cdot 29 \)
magma: Discriminant(C); Factorization(Integers()!$1);
 

Igusa-Clebsch invariants

Igusa invariants

G2 invariants

\( I_2 \)  \(=\) \(680\) \(=\)  \( 2^{3} \cdot 5 \cdot 17 \)
\( I_4 \)  \(=\) \(-5255\) \(=\)  \( - 5 \cdot 1051 \)
\( I_6 \)  \(=\) \(-1253953\) \(=\)  \( -1253953 \)
\( I_{10} \)  \(=\) \(-3712\) \(=\)  \( - 2^{7} \cdot 29 \)
\( J_2 \)  \(=\) \(680\) \(=\)  \( 2^{3} \cdot 5 \cdot 17 \)
\( J_4 \)  \(=\) \(22770\) \(=\)  \( 2 \cdot 3^{2} \cdot 5 \cdot 11 \cdot 23 \)
\( J_6 \)  \(=\) \(1180736\) \(=\)  \( 2^{6} \cdot 19 \cdot 971 \)
\( J_8 \)  \(=\) \(71106895\) \(=\)  \( 5 \cdot 223 \cdot 63773 \)
\( J_{10} \)  \(=\) \(-29696\) \(=\)  \( - 2^{10} \cdot 29 \)
\( g_1 \)  \(=\) \(-141985700000/29\)
\( g_2 \)  \(=\) \(-6991813125/29\)
\( g_3 \)  \(=\) \(-533176100/29\)

sage: C.igusa_clebsch_invariants(); [factor(a) for a in _]
 
magma: IgusaClebschInvariants(C); IgusaInvariants(C); G2Invariants(C);
 

Automorphism group

\(\mathrm{Aut}(X)\)\(\simeq\) $C_2$
magma: AutomorphismGroup(C); IdentifyGroup($1);
 
\(\mathrm{Aut}(X_{\overline{\Q}})\)\(\simeq\) $C_2$
magma: AutomorphismGroup(ChangeRing(C,AlgebraicClosure(Rationals()))); IdentifyGroup($1);
 

Rational points

All points: \((1 : 0 : 0),\, (0 : 0 : 1),\, (0 : -1 : 1),\, (-1 : -2 : 2),\, (1 : -6 : 2)\)
All points: \((1 : 0 : 0),\, (0 : 0 : 1),\, (0 : -1 : 1),\, (-1 : -2 : 2),\, (1 : -6 : 2)\)
All points: \((1 : 0 : 0),\, (0 : -1 : 1),\, (0 : 1 : 1),\, (-1 : 0 : 2),\, (1 : 0 : 2)\)

magma: [C![-1,-2,2],C![0,-1,1],C![0,0,1],C![1,-6,2],C![1,0,0]]; // minimal model
 
magma: [C![-1,0,2],C![0,-1,1],C![0,1,1],C![1,0,2],C![1,0,0]]; // simplified model
 

Number of rational Weierstrass points: \(3\)

magma: #Roots(HyperellipticPolynomials(SimplifiedModel(C)));
 

This curve is locally solvable everywhere.

magma: f,h:=HyperellipticPolynomials(C); g:=4*f+h^2; HasPointsEverywhereLocally(g,2) and (#Roots(ChangeRing(g,RealField())) gt 0 or LeadingCoefficient(g) gt 0);
 

Mordell-Weil group of the Jacobian

Group structure: \(\Z/{2}\Z \oplus \Z/{8}\Z\)

magma: MordellWeilGroupGenus2(Jacobian(C));
 

Generator $D_0$ Height Order
\((1 : -6 : 2) - (1 : 0 : 0)\) \(2x - z\) \(=\) \(0,\) \(4y\) \(=\) \(-3z^3\) \(0\) \(2\)
\((0 : 0 : 1) - (1 : 0 : 0)\) \(x\) \(=\) \(0,\) \(y\) \(=\) \(0\) \(0\) \(8\)
Generator $D_0$ Height Order
\((1 : -6 : 2) - (1 : 0 : 0)\) \(2x - z\) \(=\) \(0,\) \(4y\) \(=\) \(-3z^3\) \(0\) \(2\)
\((0 : 0 : 1) - (1 : 0 : 0)\) \(x\) \(=\) \(0,\) \(y\) \(=\) \(0\) \(0\) \(8\)
Generator $D_0$ Height Order
\(D_0 - 2 \cdot(1 : 0 : 0)\) \(2x - z\) \(=\) \(0,\) \(4y\) \(=\) \(xz^2 - 5z^3\) \(0\) \(2\)
\((0 : 1 : 1) - (1 : 0 : 0)\) \(x\) \(=\) \(0,\) \(y\) \(=\) \(xz^2 + z^3\) \(0\) \(8\)

2-torsion field: 3.1.116.1

BSD invariants

Hasse-Weil conjecture: unverified
Analytic rank: \(0\)
Mordell-Weil rank: \(0\)
2-Selmer rank:\(2\)
Regulator: \( 1 \)
Real period: \( 14.42143 \)
Tamagawa product: \( 4 \)
Torsion order:\( 16 \)
Leading coefficient: \( 0.225334 \)
Analytic order of Ш: \( 1 \)   (rounded)
Order of Ш:square

Local invariants

Prime ord(\(N\)) ord(\(\Delta\)) Tamagawa L-factor Cluster picture
\(2\) \(4\) \(10\) \(4\) \(1 + T + 2 T^{2}\)
\(29\) \(1\) \(1\) \(1\) \(( 1 + T )( 1 + 2 T + 29 T^{2} )\)

Galois representations

The mod-$\ell$ Galois representation has maximal image \(\GSp(4,\F_\ell)\) for all primes \( \ell \) except those listed.

Prime \(\ell\) mod-\(\ell\) image Is torsion prime?
\(2\) 2.120.3 yes

Sato-Tate group

\(\mathrm{ST}\)\(\simeq\) $\mathrm{USp}(4)$
\(\mathrm{ST}^0\)\(\simeq\) \(\mathrm{USp}(4)\)

Decomposition of the Jacobian

Simple over \(\overline{\Q}\)

magma: HeuristicDecompositionFactors(C);
 

Endomorphisms of the Jacobian

Not of \(\GL_2\)-type over \(\Q\)

Endomorphism ring over \(\Q\):

\(\End (J_{})\)\(\simeq\)\(\Z\)
\(\End (J_{}) \otimes \Q \)\(\simeq\)\(\Q\)
\(\End (J_{}) \otimes \R\)\(\simeq\) \(\R\)

All \(\overline{\Q}\)-endomorphisms of the Jacobian are defined over \(\Q\).

magma: //Please install CHIMP (https://github.com/edgarcosta/CHIMP) if you want to run this code
 

magma: HeuristicIsGL2(C); HeuristicEndomorphismDescription(C); HeuristicEndomorphismFieldOfDefinition(C);
 

magma: HeuristicIsGL2(C : Geometric := true); HeuristicEndomorphismDescription(C : Geometric := true); HeuristicEndomorphismLatticeDescription(C);