Properties

Label 3200.f.819200.1
Conductor $3200$
Discriminant $819200$
Mordell-Weil group \(\Z \oplus \Z/{2}\Z \oplus \Z/{6}\Z\)
Sato-Tate group $\mathrm{SU}(2)\times\mathrm{SU}(2)$
\(\End(J_{\overline{\Q}}) \otimes \R\) \(\R \times \R\)
\(\End(J_{\overline{\Q}}) \otimes \Q\) \(\Q \times \Q\)
\(\End(J) \otimes \Q\) \(\Q \times \Q\)
\(\overline{\Q}\)-simple no
\(\mathrm{GL}_2\)-type yes

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Minimal equation

Minimal equation

Simplified equation

$y^2 = x^6 - 5x^4 + 7x^2 - 2$ (homogenize, simplify)
$y^2 = x^6 - 5x^4z^2 + 7x^2z^4 - 2z^6$ (dehomogenize, simplify)
$y^2 = x^6 - 5x^4 + 7x^2 - 2$ (homogenize, minimize)

sage: R.<x> = PolynomialRing(QQ); C = HyperellipticCurve(R([-2, 0, 7, 0, -5, 0, 1]), R([]));
 
magma: R<x> := PolynomialRing(Rationals()); C := HyperellipticCurve(R![-2, 0, 7, 0, -5, 0, 1], R![]);
 
sage: X = HyperellipticCurve(R([-2, 0, 7, 0, -5, 0, 1]))
 
magma: X,pi:= SimplifiedModel(C);
 

Invariants

Conductor: \( N \)  \(=\)  \(3200\) \(=\) \( 2^{7} \cdot 5^{2} \)
magma: Conductor(LSeries(C: ExcFactors:=[*<2,Valuation(3200,2),R![1]>*])); Factorization($1);
 
Discriminant: \( \Delta \)  \(=\)  \(819200\) \(=\) \( 2^{15} \cdot 5^{2} \)
magma: Discriminant(C); Factorization(Integers()!$1);
 

Igusa-Clebsch invariants

Igusa invariants

G2 invariants

\( I_2 \)  \(=\) \(520\) \(=\)  \( 2^{3} \cdot 5 \cdot 13 \)
\( I_4 \)  \(=\) \(1141\) \(=\)  \( 7 \cdot 163 \)
\( I_6 \)  \(=\) \(186367\) \(=\)  \( 227 \cdot 821 \)
\( I_{10} \)  \(=\) \(100\) \(=\)  \( 2^{2} \cdot 5^{2} \)
\( J_2 \)  \(=\) \(2080\) \(=\)  \( 2^{5} \cdot 5 \cdot 13 \)
\( J_4 \)  \(=\) \(168096\) \(=\)  \( 2^{5} \cdot 3 \cdot 17 \cdot 103 \)
\( J_6 \)  \(=\) \(17260544\) \(=\)  \( 2^{13} \cdot 7^{2} \cdot 43 \)
\( J_8 \)  \(=\) \(1911416576\) \(=\)  \( 2^{8} \cdot 7466471 \)
\( J_{10} \)  \(=\) \(819200\) \(=\)  \( 2^{15} \cdot 5^{2} \)
\( g_1 \)  \(=\) \(47525504000\)
\( g_2 \)  \(=\) \(1846534560\)
\( g_3 \)  \(=\) \(91157248\)

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

Automorphism group

\(\mathrm{Aut}(X)\)\(\simeq\) $C_2^2$
magma: AutomorphismGroup(C); IdentifyGroup($1);
 
\(\mathrm{Aut}(X_{\overline{\Q}})\)\(\simeq\) $C_2^2$
magma: AutomorphismGroup(ChangeRing(C,AlgebraicClosure(Rationals()))); IdentifyGroup($1);
 

Rational points

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

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

Number of rational Weierstrass points: \(0\)

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: \(\Z \oplus \Z/{2}\Z \oplus \Z/{6}\Z\)

magma: MordellWeilGroupGenus2(Jacobian(C));
 

Generator $D_0$ Height Order
\(D_0 - 2 \cdot(1 : -1 : 0)\) \(z^2\) \(=\) \(0,\) \(y\) \(=\) \(x^3\) \(0.717385\) \(\infty\)
\(D_0 - (1 : -1 : 0) - (1 : 1 : 0)\) \(x^2 - xz - z^2\) \(=\) \(0,\) \(y\) \(=\) \(0\) \(0\) \(2\)
\((-1 : 1 : 1) + (1 : 1 : 1) - (1 : -1 : 0) - (1 : 1 : 0)\) \((x - z) (x + z)\) \(=\) \(0,\) \(y\) \(=\) \(z^3\) \(0\) \(6\)
Generator $D_0$ Height Order
\(D_0 - 2 \cdot(1 : -1 : 0)\) \(z^2\) \(=\) \(0,\) \(y\) \(=\) \(x^3\) \(0.717385\) \(\infty\)
\(D_0 - (1 : -1 : 0) - (1 : 1 : 0)\) \(x^2 - xz - z^2\) \(=\) \(0,\) \(y\) \(=\) \(0\) \(0\) \(2\)
\((-1 : 1 : 1) + (1 : 1 : 1) - (1 : -1 : 0) - (1 : 1 : 0)\) \((x - z) (x + z)\) \(=\) \(0,\) \(y\) \(=\) \(z^3\) \(0\) \(6\)
Generator $D_0$ Height Order
\(D_0 - 2 \cdot(1 : -1/2 : 0)\) \(z^2\) \(=\) \(0,\) \(y\) \(=\) \(1/2x^3\) \(0.717385\) \(\infty\)
\(D_0 - (1 : -1/2 : 0) - (1 : 1/2 : 0)\) \(x^2 - xz - z^2\) \(=\) \(0,\) \(y\) \(=\) \(0\) \(0\) \(2\)
\((-1 : 1/2 : 1) + (1 : 1/2 : 1) - (1 : -1/2 : 0) - (1 : 1/2 : 0)\) \((x - z) (x + z)\) \(=\) \(0,\) \(y\) \(=\) \(1/2z^3\) \(0\) \(6\)

2-torsion field: \(\Q(\sqrt{2}, \sqrt{5})\)

BSD invariants

Hasse-Weil conjecture: verified
Analytic rank: \(1\)
Mordell-Weil rank: \(1\)
2-Selmer rank:\(3\)
Regulator: \( 0.717385 \)
Real period: \( 15.39766 \)
Tamagawa product: \( 6 \)
Torsion order:\( 12 \)
Leading coefficient: \( 0.460252 \)
Analytic order of Ш: \( 1 \)   (rounded)
Order of Ш:square

Local invariants

Prime ord(\(N\)) ord(\(\Delta\)) Tamagawa L-factor Cluster picture
\(2\) \(7\) \(15\) \(6\) \(1\)
\(5\) \(2\) \(2\) \(1\) \(( 1 + T )^{2}\)

Galois representations

For primes $\ell \ge 5$ the Galois representation data has not been computed for this curve since it is not generic.

For primes $\ell \le 3$, the image of the mod-$\ell$ Galois representation is listed in the table below, whenever it is not all of $\GSp(4,\F_\ell)$.

Prime \(\ell\) mod-\(\ell\) image Is torsion prime?
\(2\) 2.180.7 yes
\(3\) 3.720.4 yes

Sato-Tate group

\(\mathrm{ST}\)\(\simeq\) $\mathrm{SU}(2)\times\mathrm{SU}(2)$
\(\mathrm{ST}^0\)\(\simeq\) \(\mathrm{SU}(2)\times\mathrm{SU}(2)\)

Decomposition of the Jacobian

Splits over \(\Q\)

Decomposes up to isogeny as the product of the non-isogenous elliptic curve isogeny classes:
  Elliptic curve isogeny class 20.a
  Elliptic curve isogeny class 160.a

magma: HeuristicDecompositionFactors(C);
 

Endomorphisms of the Jacobian

Of \(\GL_2\)-type over \(\Q\)

Endomorphism ring over \(\Q\):

\(\End (J_{})\)\(\simeq\)an order of index \(2\) in \(\Z \times \Z\)
\(\End (J_{}) \otimes \Q \)\(\simeq\)\(\Q\) \(\times\) \(\Q\)
\(\End (J_{}) \otimes \R\)\(\simeq\) \(\R \times \R\)

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);