Minimal equation
Minimal equation
Simplified equation
$y^2 + x^3y = -2x^4 + 6x^2 - 7$ | (homogenize, simplify) |
$y^2 + x^3y = -2x^4z^2 + 6x^2z^4 - 7z^6$ | (dehomogenize, simplify) |
$y^2 = x^6 - 8x^4 + 24x^2 - 28$ | (homogenize, minimize) |
sage: R.<x> = PolynomialRing(QQ); C = HyperellipticCurve(R([-7, 0, 6, 0, -2]), R([0, 0, 0, 1]));
magma: R<x> := PolynomialRing(Rationals()); C := HyperellipticCurve(R![-7, 0, 6, 0, -2], R![0, 0, 0, 1]);
sage: X = HyperellipticCurve(R([-28, 0, 24, 0, -8, 0, 1]))
magma: X,pi:= SimplifiedModel(C);
Invariants
Conductor: | \( N \) | \(=\) | \(3388\) | \(=\) | \( 2^{2} \cdot 7 \cdot 11^{2} \) | magma: Conductor(LSeries(C)); Factorization($1);
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Discriminant: | \( \Delta \) | \(=\) | \(13552\) | \(=\) | \( 2^{4} \cdot 7 \cdot 11^{2} \) | magma: Discriminant(C); Factorization(Integers()!$1);
|
Igusa-Clebsch invariants
Igusa invariants
G2 invariants
\( I_2 \) | \(=\) | \(1224\) | \(=\) | \( 2^{3} \cdot 3^{2} \cdot 17 \) |
\( I_4 \) | \(=\) | \(933\) | \(=\) | \( 3 \cdot 311 \) |
\( I_6 \) | \(=\) | \(379071\) | \(=\) | \( 3^{2} \cdot 7 \cdot 11 \cdot 547 \) |
\( I_{10} \) | \(=\) | \(1694\) | \(=\) | \( 2 \cdot 7 \cdot 11^{2} \) |
\( J_2 \) | \(=\) | \(1224\) | \(=\) | \( 2^{3} \cdot 3^{2} \cdot 17 \) |
\( J_4 \) | \(=\) | \(61802\) | \(=\) | \( 2 \cdot 13 \cdot 2377 \) |
\( J_6 \) | \(=\) | \(4119360\) | \(=\) | \( 2^{6} \cdot 3 \cdot 5 \cdot 7 \cdot 613 \) |
\( J_8 \) | \(=\) | \(305652359\) | \(=\) | \( 23 \cdot 13289233 \) |
\( J_{10} \) | \(=\) | \(13552\) | \(=\) | \( 2^{4} \cdot 7 \cdot 11^{2} \) |
\( g_1 \) | \(=\) | \(171706646513664/847\) | ||
\( g_2 \) | \(=\) | \(7083155896128/847\) | ||
\( g_3 \) | \(=\) | \(55102913280/121\) |
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);
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\(\mathrm{Aut}(X_{\overline{\Q}})\) | \(\simeq\) | $C_2^2$ | magma: AutomorphismGroup(ChangeRing(C,AlgebraicClosure(Rationals()))); IdentifyGroup($1);
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Rational points
All points: \((1 : 0 : 0),\, (1 : -1 : 0),\, (-2 : 3 : 1),\, (2 : -3 : 1),\, (-2 : 5 : 1),\, (2 : -5 : 1)\)
magma: [C![-2,3,1],C![-2,5,1],C![1,-1,0],C![1,0,0],C![2,-5,1],C![2,-3,1]]; // minimal model
magma: [C![-2,-2,1],C![-2,2,1],C![1,-1,0],C![1,1,0],C![2,-2,1],C![2,2,1]]; // 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: \(\Z \oplus \Z/{3}\Z\)
magma: MordellWeilGroupGenus2(Jacobian(C));
Generator | $D_0$ | Height | Order | |||||
---|---|---|---|---|---|---|---|---|
\(D_0 - 2 \cdot(1 : -1 : 0)\) | \(z^2\) | \(=\) | \(0,\) | \(y\) | \(=\) | \(0\) | \(0.196055\) | \(\infty\) |
\((-2 : 5 : 1) + (2 : -3 : 1) - (1 : -1 : 0) - (1 : 0 : 0)\) | \((x - 2z) (x + 2z)\) | \(=\) | \(0,\) | \(y\) | \(=\) | \(-2xz^2 + z^3\) | \(0\) | \(3\) |
Generator | $D_0$ | Height | Order | |||||
---|---|---|---|---|---|---|---|---|
\(D_0 - 2 \cdot(1 : -1 : 0)\) | \(z^2\) | \(=\) | \(0,\) | \(y\) | \(=\) | \(0\) | \(0.196055\) | \(\infty\) |
\((-2 : 5 : 1) + (2 : -3 : 1) - (1 : -1 : 0) - (1 : 0 : 0)\) | \((x - 2z) (x + 2z)\) | \(=\) | \(0,\) | \(y\) | \(=\) | \(-2xz^2 + z^3\) | \(0\) | \(3\) |
Generator | $D_0$ | Height | Order | |||||
---|---|---|---|---|---|---|---|---|
\(D_0 - 2 \cdot(1 : -1 : 0)\) | \(z^2\) | \(=\) | \(0,\) | \(y\) | \(=\) | \(x^3\) | \(0.196055\) | \(\infty\) |
\((-2 : 2 : 1) + (2 : 2 : 1) - (1 : -1 : 0) - (1 : 1 : 0)\) | \((x - 2z) (x + 2z)\) | \(=\) | \(0,\) | \(y\) | \(=\) | \(x^3 - 4xz^2 + 2z^3\) | \(0\) | \(3\) |
BSD invariants
Hasse-Weil conjecture: | verified |
Analytic rank: | \(1\) |
Mordell-Weil rank: | \(1\) |
2-Selmer rank: | \(1\) |
Regulator: | \( 0.196055 \) |
Real period: | \( 7.724076 \) |
Tamagawa product: | \( 3 \) |
Torsion order: | \( 3 \) |
Leading coefficient: | \( 0.504783 \) |
Analytic order of Ш: | \( 1 \) (rounded) |
Order of Ш: | square |
Local invariants
Prime | ord(\(N\)) | ord(\(\Delta\)) | Tamagawa | L-factor | Cluster picture |
---|---|---|---|---|---|
\(2\) | \(2\) | \(4\) | \(3\) | \(1 + 2 T^{2}\) | |
\(7\) | \(1\) | \(1\) | \(1\) | \(( 1 + T )( 1 - 2 T + 7 T^{2} )\) | |
\(11\) | \(2\) | \(2\) | \(1\) | \(( 1 + T )^{2}\) |
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? |
---|---|---|
\(2\) | 2.15.2 | no |
\(3\) | 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 44.a
Elliptic curve isogeny class 77.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);