Properties

Label 18080.c.723200.1
Conductor $18080$
Discriminant $-723200$
Mordell-Weil group \(\Z \oplus \Z \oplus \Z/{2}\Z\)
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

$y^2 + xy = x^6 - 2x^5 + x^3 + x^2 - 2x + 1$ (homogenize, simplify)
$y^2 + xz^2y = x^6 - 2x^5z + x^3z^3 + x^2z^4 - 2xz^5 + z^6$ (dehomogenize, simplify)
$y^2 = 4x^6 - 8x^5 + 4x^3 + 5x^2 - 8x + 4$ (homogenize, minimize)

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

Invariants

Conductor: \( N \)  \(=\)  \(18080\) \(=\) \( 2^{5} \cdot 5 \cdot 113 \)
magma: Conductor(LSeries(C)); Factorization($1);
 
Discriminant: \( \Delta \)  \(=\)  \(-723200\) \(=\) \( - 2^{8} \cdot 5^{2} \cdot 113 \)
magma: Discriminant(C); Factorization(Integers()!$1);
 

Igusa-Clebsch invariants

Igusa invariants

G2 invariants

\( I_2 \)  \(=\) \(148\) \(=\)  \( 2^{2} \cdot 37 \)
\( I_4 \)  \(=\) \(2917\) \(=\)  \( 2917 \)
\( I_6 \)  \(=\) \(148783\) \(=\)  \( 148783 \)
\( I_{10} \)  \(=\) \(90400\) \(=\)  \( 2^{5} \cdot 5^{2} \cdot 113 \)
\( J_2 \)  \(=\) \(148\) \(=\)  \( 2^{2} \cdot 37 \)
\( J_4 \)  \(=\) \(-1032\) \(=\)  \( - 2^{3} \cdot 3 \cdot 43 \)
\( J_6 \)  \(=\) \(-44800\) \(=\)  \( - 2^{8} \cdot 5^{2} \cdot 7 \)
\( J_8 \)  \(=\) \(-1923856\) \(=\)  \( - 2^{4} \cdot 11 \cdot 17 \cdot 643 \)
\( J_{10} \)  \(=\) \(723200\) \(=\)  \( 2^{8} \cdot 5^{2} \cdot 113 \)
\( g_1 \)  \(=\) \(277375828/2825\)
\( g_2 \)  \(=\) \(-13068474/2825\)
\( g_3 \)  \(=\) \(-153328/113\)

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

Known points
\((1 : -1 : 0)\) \((1 : 1 : 0)\) \((0 : -1 : 1)\) \((0 : 1 : 1)\) \((1 : 0 : 1)\) \((1 : -1 : 1)\)
\((-1 : -2 : 1)\) \((-1 : 3 : 1)\) \((1 : 3 : 2)\) \((3 : -1 : 2)\) \((1 : -7 : 2)\) \((3 : -11 : 2)\)
\((7 : -41 : 6)\) \((7 : -211 : 6)\)
Known points
\((1 : -1 : 0)\) \((1 : 1 : 0)\) \((0 : -1 : 1)\) \((0 : 1 : 1)\) \((1 : 0 : 1)\) \((1 : -1 : 1)\)
\((-1 : -2 : 1)\) \((-1 : 3 : 1)\) \((1 : 3 : 2)\) \((3 : -1 : 2)\) \((1 : -7 : 2)\) \((3 : -11 : 2)\)
\((7 : -41 : 6)\) \((7 : -211 : 6)\)
Known points
\((1 : -2 : 0)\) \((1 : 2 : 0)\) \((1 : -1 : 1)\) \((1 : 1 : 1)\) \((0 : -2 : 1)\) \((0 : 2 : 1)\)
\((-1 : -5 : 1)\) \((-1 : 5 : 1)\) \((1 : -10 : 2)\) \((1 : 10 : 2)\) \((3 : -10 : 2)\) \((3 : 10 : 2)\)
\((7 : -170 : 6)\) \((7 : 170 : 6)\)

magma: [C![-1,-2,1],C![-1,3,1],C![0,-1,1],C![0,1,1],C![1,-7,2],C![1,-1,0],C![1,-1,1],C![1,0,1],C![1,1,0],C![1,3,2],C![3,-11,2],C![3,-1,2],C![7,-211,6],C![7,-41,6]]; // minimal model
 
magma: [C![-1,-5,1],C![-1,5,1],C![0,-2,1],C![0,2,1],C![1,-10,2],C![1,-2,0],C![1,-1,1],C![1,1,1],C![1,2,0],C![1,10,2],C![3,-10,2],C![3,10,2],C![7,-170,6],C![7,170,6]]; // 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: \(\Z \oplus \Z \oplus \Z/{2}\Z\)

magma: MordellWeilGroupGenus2(Jacobian(C));
 

Generator $D_0$ Height Order
\((0 : -1 : 1) - (1 : 1 : 0)\) \(z x\) \(=\) \(0,\) \(y\) \(=\) \(-x^3 - z^3\) \(0.557085\) \(\infty\)
\((0 : -1 : 1) + (3 : -11 : 2) - (1 : -1 : 0) - (1 : 1 : 0)\) \(x (2x - 3z)\) \(=\) \(0,\) \(4y\) \(=\) \(-xz^2 - 4z^3\) \(0.039896\) \(\infty\)
\(D_0 - (1 : -1 : 0) - (1 : 1 : 0)\) \(2x^2 - 2xz + z^2\) \(=\) \(0,\) \(2y\) \(=\) \(-xz^2\) \(0\) \(2\)
Generator $D_0$ Height Order
\((0 : -1 : 1) - (1 : 1 : 0)\) \(z x\) \(=\) \(0,\) \(y\) \(=\) \(-x^3 - z^3\) \(0.557085\) \(\infty\)
\((0 : -1 : 1) + (3 : -11 : 2) - (1 : -1 : 0) - (1 : 1 : 0)\) \(x (2x - 3z)\) \(=\) \(0,\) \(4y\) \(=\) \(-xz^2 - 4z^3\) \(0.039896\) \(\infty\)
\(D_0 - (1 : -1 : 0) - (1 : 1 : 0)\) \(2x^2 - 2xz + z^2\) \(=\) \(0,\) \(2y\) \(=\) \(-xz^2\) \(0\) \(2\)
Generator $D_0$ Height Order
\((0 : -2 : 1) - (1 : 2 : 0)\) \(z x\) \(=\) \(0,\) \(y\) \(=\) \(-2x^3 + xz^2 - 2z^3\) \(0.557085\) \(\infty\)
\(2 \cdot(0 : -2 : 1) - (1 : -2 : 0) - (1 : 2 : 0)\) \(x (2x - 3z)\) \(=\) \(0,\) \(4y\) \(=\) \(-xz^2 - 8z^3\) \(0.039896\) \(\infty\)
\(D_0 - (1 : -2 : 0) - (1 : 2 : 0)\) \(2x^2 - 2xz + z^2\) \(=\) \(0,\) \(2y\) \(=\) \(-xz^2\) \(0\) \(2\)

2-torsion field: 4.0.1808.1

BSD invariants

Hasse-Weil conjecture: unverified
Analytic rank: \(2\)
Mordell-Weil rank: \(2\)
2-Selmer rank:\(3\)
Regulator: \( 0.022196 \)
Real period: \( 14.76743 \)
Tamagawa product: \( 8 \)
Torsion order:\( 2 \)
Leading coefficient: \( 0.655575 \)
Analytic order of Ш: \( 1 \)   (rounded)
Order of Ш:square

Local invariants

Prime ord(\(N\)) ord(\(\Delta\)) Tamagawa L-factor Cluster picture
\(2\) \(5\) \(8\) \(4\) \(1 + T\)
\(5\) \(1\) \(2\) \(2\) \(( 1 + T )( 1 + 2 T + 5 T^{2} )\)
\(113\) \(1\) \(1\) \(1\) \(( 1 + T )( 1 + 14 T + 113 T^{2} )\)

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?
\(2\) 2.90.1 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);