Properties

Label 1915.a.1915.1
Conductor $1915$
Discriminant $1915$
Mordell-Weil group \(\Z\)
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

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

sage: R.<x> = PolynomialRing(QQ); C = HyperellipticCurve(R([0, -1, 0, 0, -2, 0, 1]), R([1, 1, 0, 1]));
 
magma: R<x> := PolynomialRing(Rationals()); C := HyperellipticCurve(R![0, -1, 0, 0, -2, 0, 1], R![1, 1, 0, 1]);
 
sage: X = HyperellipticCurve(R([1, -2, 1, 2, -6, 0, 5]))
 
magma: X,pi:= SimplifiedModel(C);
 

Invariants

Conductor: \( N \)  \(=\)  \(1915\) \(=\) \( 5 \cdot 383 \)
magma: Conductor(LSeries(C)); Factorization($1);
 
Discriminant: \( \Delta \)  \(=\)  \(1915\) \(=\) \( 5 \cdot 383 \)
magma: Discriminant(C); Factorization(Integers()!$1);
 

Igusa-Clebsch invariants

Igusa invariants

G2 invariants

\( I_2 \)  \(=\) \(540\) \(=\)  \( 2^{2} \cdot 3^{3} \cdot 5 \)
\( I_4 \)  \(=\) \(5361\) \(=\)  \( 3 \cdot 1787 \)
\( I_6 \)  \(=\) \(1155735\) \(=\)  \( 3^{3} \cdot 5 \cdot 7 \cdot 1223 \)
\( I_{10} \)  \(=\) \(-245120\) \(=\)  \( - 2^{7} \cdot 5 \cdot 383 \)
\( J_2 \)  \(=\) \(135\) \(=\)  \( 3^{3} \cdot 5 \)
\( J_4 \)  \(=\) \(536\) \(=\)  \( 2^{3} \cdot 67 \)
\( J_6 \)  \(=\) \(-1980\) \(=\)  \( - 2^{2} \cdot 3^{2} \cdot 5 \cdot 11 \)
\( J_8 \)  \(=\) \(-138649\) \(=\)  \( - 7 \cdot 29 \cdot 683 \)
\( J_{10} \)  \(=\) \(-1915\) \(=\)  \( - 5 \cdot 383 \)
\( g_1 \)  \(=\) \(-8968066875/383\)
\( g_2 \)  \(=\) \(-263752200/383\)
\( g_3 \)  \(=\) \(7217100/383\)

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
\((0 : 0 : 1)\) \((-1 : 0 : 1)\) \((0 : -1 : 1)\) \((-1 : 1 : 1)\) \((1 : -1 : 1)\) \((1 : -2 : 1)\)
\((12 : -1196 : 11)\) \((12 : -3315 : 11)\)
All points
\((0 : 0 : 1)\) \((-1 : 0 : 1)\) \((0 : -1 : 1)\) \((-1 : 1 : 1)\) \((1 : -1 : 1)\) \((1 : -2 : 1)\)
\((12 : -1196 : 11)\) \((12 : -3315 : 11)\)
All points
\((0 : -1 : 1)\) \((0 : 1 : 1)\) \((-1 : -1 : 1)\) \((-1 : 1 : 1)\) \((1 : -1 : 1)\) \((1 : 1 : 1)\)
\((12 : -2119 : 11)\) \((12 : 2119 : 11)\)

magma: [C![-1,0,1],C![-1,1,1],C![0,-1,1],C![0,0,1],C![1,-2,1],C![1,-1,1],C![12,-3315,11],C![12,-1196,11]]; // minimal model
 
magma: [C![-1,-1,1],C![-1,1,1],C![0,-1,1],C![0,1,1],C![1,-1,1],C![1,1,1],C![12,-2119,11],C![12,2119,11]]; // 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: \(\Z\)

magma: MordellWeilGroupGenus2(Jacobian(C));
 

Generator $D_0$ Height Order
\(2 \cdot(0 : 0 : 1) - D_\infty\) \(x^2\) \(=\) \(0,\) \(y\) \(=\) \(-xz^2\) \(0.011347\) \(\infty\)
Generator $D_0$ Height Order
\(2 \cdot(0 : 0 : 1) - D_\infty\) \(x^2\) \(=\) \(0,\) \(y\) \(=\) \(-xz^2\) \(0.011347\) \(\infty\)
Generator $D_0$ Height Order
\(2 \cdot(0 : 1 : 1) - D_\infty\) \(x^2\) \(=\) \(0,\) \(y\) \(=\) \(x^3 - xz^2 + z^3\) \(0.011347\) \(\infty\)

2-torsion field: 6.2.122560.1

BSD invariants

Hasse-Weil conjecture: unverified
Analytic rank: \(1\)
Mordell-Weil rank: \(1\)
2-Selmer rank:\(1\)
Regulator: \( 0.011347 \)
Real period: \( 27.60289 \)
Tamagawa product: \( 1 \)
Torsion order:\( 1 \)
Leading coefficient: \( 0.313228 \)
Analytic order of Ш: \( 1 \)   (rounded)
Order of Ш:square

Local invariants

Prime ord(\(N\)) ord(\(\Delta\)) Tamagawa L-factor Cluster picture
\(5\) \(1\) \(1\) \(1\) \(( 1 - T )( 1 + 4 T + 5 T^{2} )\)
\(383\) \(1\) \(1\) \(1\) \(( 1 + T )( 1 - 21 T + 383 T^{2} )\)

Galois representations

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

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);