Properties

Label 589824.c.589824.1
Conductor $589824$
Discriminant $589824$
Mordell-Weil group \(\Z \oplus \Z/{2}\Z\)
Sato-Tate group $J(E_2)$
\(\End(J_{\overline{\Q}}) \otimes \R\) \(\mathrm{M}_2(\R)\)
\(\End(J_{\overline{\Q}}) \otimes \Q\) \(\mathrm{M}_2(\Q)\)
\(\End(J) \otimes \Q\) \(\Q\)
\(\overline{\Q}\)-simple no
\(\mathrm{GL}_2\)-type no

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Minimal equation

Minimal equation

Simplified equation

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

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

Invariants

Conductor: \( N \)  \(=\)  \(589824\) \(=\) \( 2^{16} \cdot 3^{2} \)
magma: Conductor(LSeries(C: ExcFactors:=[*<2,Valuation(589824,2),R![1]>*])); Factorization($1);
 
Discriminant: \( \Delta \)  \(=\)  \(589824\) \(=\) \( 2^{16} \cdot 3^{2} \)
magma: Discriminant(C); Factorization(Integers()!$1);
 

Igusa-Clebsch invariants

Igusa invariants

G2 invariants

\( I_2 \)  \(=\) \(196\) \(=\)  \( 2^{2} \cdot 7^{2} \)
\( I_4 \)  \(=\) \(892\) \(=\)  \( 2^{2} \cdot 223 \)
\( I_6 \)  \(=\) \(55928\) \(=\)  \( 2^{3} \cdot 6991 \)
\( I_{10} \)  \(=\) \(72\) \(=\)  \( 2^{3} \cdot 3^{2} \)
\( J_2 \)  \(=\) \(784\) \(=\)  \( 2^{4} \cdot 7^{2} \)
\( J_4 \)  \(=\) \(16096\) \(=\)  \( 2^{5} \cdot 503 \)
\( J_6 \)  \(=\) \(5888\) \(=\)  \( 2^{8} \cdot 23 \)
\( J_8 \)  \(=\) \(-63616256\) \(=\)  \( - 2^{8} \cdot 11 \cdot 19 \cdot 29 \cdot 41 \)
\( J_{10} \)  \(=\) \(589824\) \(=\)  \( 2^{16} \cdot 3^{2} \)
\( g_1 \)  \(=\) \(4519603984/9\)
\( g_2 \)  \(=\) \(118354894/9\)
\( g_3 \)  \(=\) \(55223/9\)

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

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

Number of rational Weierstrass points: \(2\)

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

magma: MordellWeilGroupGenus2(Jacobian(C));
 

Generator $D_0$ Height Order
\(D_0 - 2 \cdot(1 : 0 : 0)\) \(x^2 - 3z^2\) \(=\) \(0,\) \(y\) \(=\) \(xz^2 - z^3\) \(1.017766\) \(\infty\)
\((2 : 0 : 1) - (1 : 0 : 0)\) \(x - 2z\) \(=\) \(0,\) \(y\) \(=\) \(0\) \(0\) \(2\)
Generator $D_0$ Height Order
\(D_0 - 2 \cdot(1 : 0 : 0)\) \(x^2 - 3z^2\) \(=\) \(0,\) \(y\) \(=\) \(xz^2 - z^3\) \(1.017766\) \(\infty\)
\((2 : 0 : 1) - (1 : 0 : 0)\) \(x - 2z\) \(=\) \(0,\) \(y\) \(=\) \(0\) \(0\) \(2\)
Generator $D_0$ Height Order
\(D_0 - 2 \cdot(1 : 0 : 0)\) \(x^2 - 3z^2\) \(=\) \(0,\) \(y\) \(=\) \(1/2xz^2 - 1/2z^3\) \(1.017766\) \(\infty\)
\((2 : 0 : 1) - (1 : 0 : 0)\) \(x - 2z\) \(=\) \(0,\) \(y\) \(=\) \(0\) \(0\) \(2\)

2-torsion field: \(\Q(\sqrt{2}, \sqrt{3})\)

BSD invariants

Hasse-Weil conjecture: unverified
Analytic rank: \(1\)
Mordell-Weil rank: \(1\)
2-Selmer rank:\(2\)
Regulator: \( 1.017766 \)
Real period: \( 15.38717 \)
Tamagawa product: \( 1 \)
Torsion order:\( 2 \)
Leading coefficient: \( 3.915138 \)
Analytic order of Ш: \( 1 \)   (rounded)
Order of Ш:square

Local invariants

Prime ord(\(N\)) ord(\(\Delta\)) Tamagawa L-factor Cluster picture
\(2\) \(16\) \(16\) \(1\) \(1\)
\(3\) \(2\) \(2\) \(1\) \(1 + T^{2}\)

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?
\(2\) 2.180.5 yes
\(3\) 3.540.2 no

Sato-Tate group

\(\mathrm{ST}\)\(\simeq\) $J(E_2)$
\(\mathrm{ST}^0\)\(\simeq\) \(\mathrm{SU}(2)\)

Decomposition of the Jacobian

Splits over the number field \(\Q (b) \simeq \) \(\Q(\zeta_{8})\) with defining polynomial:
  \(x^{4} + 1\)

Decomposes up to isogeny as the square of the elliptic curve isogeny class:
  \(y^2 = x^3 - g_4 / 48 x - g_6 / 864\) with
  \(g_4 = -1024 b^{3} - 3072 b^{2} - 3584 b - 1920\)
  \(g_6 = 329728 b^{3} + 100352 b^{2} - 186368 b - 368640\)
   Conductor norm: 5308416

magma: HeuristicDecompositionFactors(C);
 

Endomorphisms of the Jacobian

Not of \(\GL_2\)-type over \(\Q\)

Endomorphism ring over \(\Q\):

\(\End (J_{})\)\(\simeq\)\(\Z\)
\(\End (J_{}) \otimes \Q \)\(\simeq\)\(\Q\)
\(\End (J_{}) \otimes \R\)\(\simeq\) \(\R\)

Smallest field over which all endomorphisms are defined:
Galois number field \(K = \Q (a) \simeq \) \(\Q(\zeta_{8})\) with defining polynomial \(x^{4} + 1\)

Not of \(\GL_2\)-type over \(\overline{\Q}\)

Endomorphism ring over \(\overline{\Q}\):

\(\End (J_{\overline{\Q}})\)\(\simeq\)a non-Eichler order of index \(16\) in a maximal order of \(\End (J_{\overline{\Q}}) \otimes \Q\)
\(\End (J_{\overline{\Q}}) \otimes \Q \)\(\simeq\)\(\mathrm{M}_2(\)\(\Q\)\()\)
\(\End (J_{\overline{\Q}}) \otimes \R\)\(\simeq\) \(\mathrm{M}_2 (\R)\)

Remainder of the endomorphism lattice by field

Over subfield \(F \simeq \) \(\Q(\sqrt{-2}) \) with generator \(-a^{3} - a\) with minimal polynomial \(x^{2} + 2\):

\(\End (J_{F})\)\(\simeq\)\(\Z [2\sqrt{-1}]\)
\(\End (J_{F}) \otimes \Q \)\(\simeq\)\(\Q(\sqrt{-1}) \)
\(\End (J_{F}) \otimes \R\)\(\simeq\) \(\C\)
  Sato Tate group: $E_2$
  Of \(\GL_2\)-type, simple

Over subfield \(F \simeq \) \(\Q(\sqrt{2}) \) with generator \(a^{3} - a\) with minimal polynomial \(x^{2} - 2\):

\(\End (J_{F})\)\(\simeq\)\(\Z [\sqrt{2}]\)
\(\End (J_{F}) \otimes \Q \)\(\simeq\)\(\Q(\sqrt{2}) \)
\(\End (J_{F}) \otimes \R\)\(\simeq\) \(\R \times \R\)
  Sato Tate group: $J(E_1)$
  Of \(\GL_2\)-type, simple

Over subfield \(F \simeq \) \(\Q(\sqrt{-1}) \) with generator \(-a^{2}\) with minimal polynomial \(x^{2} + 1\):

\(\End (J_{F})\)\(\simeq\)\(\Z [\sqrt{2}]\)
\(\End (J_{F}) \otimes \Q \)\(\simeq\)\(\Q(\sqrt{2}) \)
\(\End (J_{F}) \otimes \R\)\(\simeq\) \(\R \times \R\)
  Sato Tate group: $J(E_1)$
  Of \(\GL_2\)-type, simple

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);