Minimal equation
magma: R<x> := PolynomialRing(Rationals()); C := HyperellipticCurve(R![-1, 0, 2, 4, 2, 0, -1], R![1, 1, 1, 1]);
sage: R.<x> = PolynomialRing(QQ); C = HyperellipticCurve(R([-1, 0, 2, 4, 2, 0, -1]), R([1, 1, 1, 1]))
$y^2 + (x^3 + x^2 + x + 1)y = -x^6 + 2x^4 + 4x^3 + 2x^2 - 1$
Invariants
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magma: Conductor(LSeries(C)); Factorization($1);
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| \( N \) | = | \( 800 \) | = | \( 2^{5} \cdot 5^{2} \) | |
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magma: Discriminant(C); Factorization(Integers()!$1);
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| \( \Delta \) | = | \(8000\) | = | \( 2^{6} \cdot 5^{3} \) | |
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);
| \( I_2 \) | = | \(-1536\) | = | \( -1 \cdot 2^{9} \cdot 3 \) |
| \( I_4 \) | = | \(742656\) | = | \( 2^{8} \cdot 3 \cdot 967 \) |
| \( I_6 \) | = | \(-165064704\) | = | \( -1 \cdot 2^{12} \cdot 3 \cdot 7 \cdot 19 \cdot 101 \) |
| \( I_{10} \) | = | \(32768000\) | = | \( 2^{18} \cdot 5^{3} \) |
| \( J_2 \) | = | \(-192\) | = | \( -1 \cdot 2^{6} \cdot 3 \) |
| \( J_4 \) | = | \(-6200\) | = | \( -1 \cdot 2^{3} \cdot 5^{2} \cdot 31 \) |
| \( J_6 \) | = | \(-142400\) | = | \( -1 \cdot 2^{6} \cdot 5^{2} \cdot 89 \) |
| \( J_8 \) | = | \(-2774800\) | = | \( -1 \cdot 2^{4} \cdot 5^{2} \cdot 7 \cdot 991 \) |
| \( J_{10} \) | = | \(8000\) | = | \( 2^{6} \cdot 5^{3} \) |
| \( g_1 \) | = | \(-4076863488/125\) | ||
| \( g_2 \) | = | \(27426816/5\) | ||
| \( g_3 \) | = | \(-3280896/5\) |
Automorphism group
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magma: AutomorphismGroup(C); IdentifyGroup($1);
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| \(\mathrm{Aut}(X)\) | \(\simeq\) | \(V_4 \) | (GAP id : [4,2]) | ||
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magma: AutomorphismGroup(ChangeRing(C,AlgebraicClosure(Rationals()))); IdentifyGroup($1);
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| \(\mathrm{Aut}(X_{\overline{\Q}})\) | \(\simeq\) | \(V_4 \) | (GAP id : [4,2]) | ||
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 $\Q_{2}$ and $\Q_{5}$.
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: 5.5900502537976426371625921293
Tamagawa numbers: 1 (p = 2), 1 (p = 5)
magma: TorsionSubgroup(Jacobian(SimplifiedModel(C))); AbelianInvariants($1);
Torsion: \(\Z/{4}\Z\)
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 20.a1
Elliptic curve 40.a3
Endomorphisms
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 \(\Q\).