Properties

Label 784.b.76832.1
Conductor 784
Discriminant -76832
Sato-Tate group $G_{3,3}$
\(\End(J_{\overline{\Q}}) \otimes \R\) \(\R \times \R\)
\(\End(J_{\overline{\Q}}) \otimes \Q\) \(\Q \times \Q\)
\(\overline{\Q}\)-simple no
\(\mathrm{GL}_2\)-type yes

Related objects

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Show commands for: Magma / SageMath

Minimal equation

magma: R<x> := PolynomialRing(Rationals()); C := HyperellipticCurve(R![-9, 10, 0, -2, -4, 4, -1], R![1, 1]);
 
sage: R.<x> = PolynomialRing(QQ); C = HyperellipticCurve(R([-9, 10, 0, -2, -4, 4, -1]), R([1, 1]))
 

$y^2 + (x + 1)y = -x^6 + 4x^5 - 4x^4 - 2x^3 + 10x - 9$

Invariants

magma: Conductor(LSeries(C)); Factorization($1);
 
\( N \)  =  \( 784 \)  =  \( 2^{4} \cdot 7^{2} \)
magma: Discriminant(C); Factorization(Integers()!$1);
 
\( \Delta \)  =  \(-76832\)  =  \( -1 \cdot 2^{5} \cdot 7^{4} \)

Igusa-Clebsch invariants

magma: IgusaClebschInvariants(C); [Factorization(Integers()!a): a in $1];
 
sage: C.igusa_clebsch_invariants(); [factor(a) for a in _]
 

Igusa invariants

magma: IgusaInvariants(C); [Factorization(Integers()!a): a in $1];
 

G2 invariants

magma: G2Invariants(C);
 

\( I_2 \)  =  \(-6080\)  =  \( -1 \cdot 2^{6} \cdot 5 \cdot 19 \)
\( I_4 \)  =  \(2116480\)  =  \( 2^{7} \cdot 5 \cdot 3307 \)
\( I_6 \)  =  \(-3262676224\)  =  \( -1 \cdot 2^{8} \cdot 23 \cdot 554123 \)
\( I_{10} \)  =  \(-314703872\)  =  \( -1 \cdot 2^{17} \cdot 7^{4} \)
\( J_2 \)  =  \(-760\)  =  \( -1 \cdot 2^{3} \cdot 5 \cdot 19 \)
\( J_4 \)  =  \(2020\)  =  \( 2^{2} \cdot 5 \cdot 101 \)
\( J_6 \)  =  \(-6076\)  =  \( -1 \cdot 2^{2} \cdot 7^{2} \cdot 31 \)
\( J_8 \)  =  \(134340\)  =  \( 2^{2} \cdot 3 \cdot 5 \cdot 2239 \)
\( J_{10} \)  =  \(-76832\)  =  \( -1 \cdot 2^{5} \cdot 7^{4} \)
\( g_1 \)  =  \(7923516800000/2401\)
\( g_2 \)  =  \(27710360000/2401\)
\( g_3 \)  =  \(2238200/49\)
Alternative geometric invariants: Igusa-Clebsch, Igusa, G2

Automorphism group

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

Rational points

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);
 

This curve is locally solvable except over $\R$ and $\Q_{2}$.

magma: [];
 

There are no rational points.

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

Number of rational Weierstrass points: \(0\)

Invariants of the Jacobian:

Analytic rank: \(0\)

magma: TwoSelmerGroup(Jacobian(C)); NumberOfGenerators($1);
 

2-Selmer rank: \(1\)

magma: HasSquareSha(Jacobian(C));
 

Order of Ш*: square

Regulator: 1.0

Real period: 3.7567000978383574081349145505

Tamagawa numbers: 1 (p = 2), 3 (p = 7)

magma: TorsionSubgroup(Jacobian(SimplifiedModel(C))); AbelianInvariants($1);
 

Torsion: \(\Z/{6}\Z\)

2-torsion field: 8.0.3211264.1

Sato-Tate group

\(\mathrm{ST}\)\(\simeq\) $G_{3,3}$
\(\mathrm{ST}^0\)\(\simeq\) \(\mathrm{SU}(2)\times\mathrm{SU}(2)\)

Decomposition

Splits over \(\Q\)

Decomposes up to isogeny as the product of the non-isogenous elliptic curves:
  Elliptic curve 56.b2
  Elliptic curve 14.a6

Endomorphisms

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

Endomorphism ring over \(\Q\):
\(\End (J_{})\)\(\simeq\)an order of index \(4\) 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 \(\Q\).