Properties

Label 6672.a.720576.1
Conductor $6672$
Discriminant $-720576$
Mordell-Weil group \(\Z \oplus \Z/{2}\Z \oplus \Z/{4}\Z\)
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

$y^2 + xy = 2x^5 - 4x^4 - x^3 + 5x^2 - 2x$ (homogenize, simplify)
$y^2 + xz^2y = 2x^5z - 4x^4z^2 - x^3z^3 + 5x^2z^4 - 2xz^5$ (dehomogenize, simplify)
$y^2 = 8x^5 - 16x^4 - 4x^3 + 21x^2 - 8x$ (homogenize, minimize)

sage: R.<x> = PolynomialRing(QQ); C = HyperellipticCurve(R([0, -2, 5, -1, -4, 2]), R([0, 1]));
 
magma: R<x> := PolynomialRing(Rationals()); C := HyperellipticCurve(R![0, -2, 5, -1, -4, 2], R![0, 1]);
 
sage: X = HyperellipticCurve(R([0, -8, 21, -4, -16, 8]))
 
magma: X,pi:= SimplifiedModel(C);
 

Invariants

Conductor: \( N \)  \(=\)  \(6672\) \(=\) \( 2^{4} \cdot 3 \cdot 139 \)
magma: Conductor(LSeries(C)); Factorization($1);
 
Discriminant: \( \Delta \)  \(=\)  \(-720576\) \(=\) \( - 2^{6} \cdot 3^{4} \cdot 139 \)
magma: Discriminant(C); Factorization(Integers()!$1);
 

Igusa-Clebsch invariants

Igusa invariants

G2 invariants

\( I_2 \)  \(=\) \(728\) \(=\)  \( 2^{3} \cdot 7 \cdot 13 \)
\( I_4 \)  \(=\) \(15256\) \(=\)  \( 2^{3} \cdot 1907 \)
\( I_6 \)  \(=\) \(3297276\) \(=\)  \( 2^{2} \cdot 3^{2} \cdot 91591 \)
\( I_{10} \)  \(=\) \(-2882304\) \(=\)  \( - 2^{8} \cdot 3^{4} \cdot 139 \)
\( J_2 \)  \(=\) \(364\) \(=\)  \( 2^{2} \cdot 7 \cdot 13 \)
\( J_4 \)  \(=\) \(2978\) \(=\)  \( 2 \cdot 1489 \)
\( J_6 \)  \(=\) \(2368\) \(=\)  \( 2^{6} \cdot 37 \)
\( J_8 \)  \(=\) \(-2001633\) \(=\)  \( - 3 \cdot 667211 \)
\( J_{10} \)  \(=\) \(-720576\) \(=\)  \( - 2^{6} \cdot 3^{4} \cdot 139 \)
\( g_1 \)  \(=\) \(-99845143216/11259\)
\( g_2 \)  \(=\) \(-2244134438/11259\)
\( g_3 \)  \(=\) \(-4902352/11259\)

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
\((1 : 0 : 0)\) \((0 : 0 : 1)\) \((1 : 0 : 1)\) \((-1 : -1 : 1)\) \((1 : -1 : 1)\) \((-1 : 2 : 1)\)
\((1 : -2 : 2)\) \((2 : 2 : 1)\) \((2 : -4 : 1)\) \((25 : -2010 : 18)\) \((25 : -6090 : 18)\)
All points
\((1 : 0 : 0)\) \((0 : 0 : 1)\) \((1 : 0 : 1)\) \((-1 : -1 : 1)\) \((1 : -1 : 1)\) \((-1 : 2 : 1)\)
\((1 : -2 : 2)\) \((2 : 2 : 1)\) \((2 : -4 : 1)\) \((25 : -2010 : 18)\) \((25 : -6090 : 18)\)
All points
\((1 : 0 : 0)\) \((0 : 0 : 1)\) \((1 : -1 : 1)\) \((1 : 1 : 1)\) \((1 : 0 : 2)\) \((-1 : -3 : 1)\)
\((-1 : 3 : 1)\) \((2 : -6 : 1)\) \((2 : 6 : 1)\) \((25 : -4080 : 18)\) \((25 : 4080 : 18)\)

magma: [C![-1,-1,1],C![-1,2,1],C![0,0,1],C![1,-2,2],C![1,-1,1],C![1,0,0],C![1,0,1],C![2,-4,1],C![2,2,1],C![25,-6090,18],C![25,-2010,18]]; // minimal model
 
magma: [C![-1,-3,1],C![-1,3,1],C![0,0,1],C![1,0,2],C![1,-1,1],C![1,0,0],C![1,1,1],C![2,-6,1],C![2,6,1],C![25,-4080,18],C![25,4080,18]]; // 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: \(\Z \oplus \Z/{2}\Z \oplus \Z/{4}\Z\)

magma: MordellWeilGroupGenus2(Jacobian(C));
 

Generator $D_0$ Height Order
\((-1 : -1 : 1) + (1 : -1 : 1) - 2 \cdot(1 : 0 : 0)\) \((x - z) (x + z)\) \(=\) \(0,\) \(y\) \(=\) \(-z^3\) \(0.157524\) \(\infty\)
\((0 : 0 : 1) + (1 : -2 : 2) - 2 \cdot(1 : 0 : 0)\) \(x (2x - z)\) \(=\) \(0,\) \(2y\) \(=\) \(-xz^2\) \(0\) \(2\)
\((1 : -1 : 1) + (2 : 2 : 1) - 2 \cdot(1 : 0 : 0)\) \((x - 2z) (x - z)\) \(=\) \(0,\) \(y\) \(=\) \(3xz^2 - 4z^3\) \(0\) \(4\)
Generator $D_0$ Height Order
\((-1 : -1 : 1) + (1 : -1 : 1) - 2 \cdot(1 : 0 : 0)\) \((x - z) (x + z)\) \(=\) \(0,\) \(y\) \(=\) \(-z^3\) \(0.157524\) \(\infty\)
\((0 : 0 : 1) + (1 : -2 : 2) - 2 \cdot(1 : 0 : 0)\) \(x (2x - z)\) \(=\) \(0,\) \(2y\) \(=\) \(-xz^2\) \(0\) \(2\)
\((1 : -1 : 1) + (2 : 2 : 1) - 2 \cdot(1 : 0 : 0)\) \((x - 2z) (x - z)\) \(=\) \(0,\) \(y\) \(=\) \(3xz^2 - 4z^3\) \(0\) \(4\)
Generator $D_0$ Height Order
\((-1 : -3 : 1) + (1 : -1 : 1) - 2 \cdot(1 : 0 : 0)\) \((x - z) (x + z)\) \(=\) \(0,\) \(y\) \(=\) \(xz^2 - 2z^3\) \(0.157524\) \(\infty\)
\((0 : 0 : 1) - (1 : 0 : 0)\) \(x (2x - z)\) \(=\) \(0,\) \(2y\) \(=\) \(-xz^2\) \(0\) \(2\)
\((1 : -1 : 1) + (2 : 6 : 1) - 2 \cdot(1 : 0 : 0)\) \((x - 2z) (x - z)\) \(=\) \(0,\) \(y\) \(=\) \(7xz^2 - 8z^3\) \(0\) \(4\)

2-torsion field: 3.1.139.1

BSD invariants

Hasse-Weil conjecture: unverified
Analytic rank: \(1\)
Mordell-Weil rank: \(1\)
2-Selmer rank:\(3\)
Regulator: \( 0.157524 \)
Real period: \( 15.89105 \)
Tamagawa product: \( 16 \)
Torsion order:\( 8 \)
Leading coefficient: \( 0.625807 \)
Analytic order of Ш: \( 1 \)   (rounded)
Order of Ш:square

Local invariants

Prime ord(\(N\)) ord(\(\Delta\)) Tamagawa L-factor Cluster picture
\(2\) \(4\) \(6\) \(4\) \(1 + T\)
\(3\) \(1\) \(4\) \(4\) \(( 1 - T )( 1 + 2 T + 3 T^{2} )\)
\(139\) \(1\) \(1\) \(1\) \(( 1 - T )( 1 + 4 T + 139 T^{2} )\)

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);