Properties

Label 448.a.448.2
Conductor 448
Discriminant -448
Sato-Tate group $N(G_{1,3})$
\(\End(J_{\overline{\Q}}) \otimes \R\) \(\C \times \R\)
\(\End(J_{\overline{\Q}}) \otimes \Q\) \(\mathrm{CM} \times \Q\)
\(\overline{\Q}\)-simple no
\(\mathrm{GL}_2\)-type yes

Related objects

Learn more about

Show commands for: Magma / SageMath

Minimal equation

magma: R<x> := PolynomialRing(Rationals()); C := HyperellipticCurve(R![7, 0, 0, 0, -2], R![0, 1, 0, 1]);
sage: R.<x> = PolynomialRing(QQ); C = HyperellipticCurve(R([7, 0, 0, 0, -2]), R([0, 1, 0, 1]))

$y^2 + (x^3 + x)y = -2x^4 + 7$

Invariants

magma: Conductor(LSeries(C)); Factorization($1);
\( N \)  =  \( 448 \)  =  \( 2^{6} \cdot 7 \)
magma: Discriminant(C); Factorization(Integers()!$1);
\( \Delta \)  =  \(-448\)  =  \( -1 \cdot 2^{6} \cdot 7 \)

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);

\( I_2 \)  =  \(-6624\)  =  \( -1 \cdot 2^{5} \cdot 3^{2} \cdot 23 \)
\( I_4 \)  =  \(1064640\)  =  \( 2^{6} \cdot 3 \cdot 5 \cdot 1109 \)
\( I_6 \)  =  \(-2717927424\)  =  \( -1 \cdot 2^{11} \cdot 3^{2} \cdot 147457 \)
\( I_{10} \)  =  \(-1835008\)  =  \( -1 \cdot 2^{18} \cdot 7 \)
\( J_2 \)  =  \(-828\)  =  \( -1 \cdot 2^{2} \cdot 3^{2} \cdot 23 \)
\( J_4 \)  =  \(17476\)  =  \( 2^{2} \cdot 17 \cdot 257 \)
\( J_6 \)  =  \(853888\)  =  \( 2^{7} \cdot 7 \cdot 953 \)
\( J_8 \)  =  \(-253107460\)  =  \( -1 \cdot 2^{2} \cdot 5 \cdot 43 \cdot 294311 \)
\( J_{10} \)  =  \(-448\)  =  \( -1 \cdot 2^{6} \cdot 7 \)
\( g_1 \)  =  \(6080953884912/7\)
\( g_2 \)  =  \(155007628668/7\)
\( g_3 \)  =  \(-1306723104\)
Alternative geometric invariants: Igusa-Clebsch, Igusa, G2

Automorphism group

magma: AutomorphismGroup(C); IdentifyGroup($1);
\(\mathrm{Aut}(X)\)\(\simeq\) \(V_4 \) (GAP id : [4,2])
magma: AutomorphismGroup(ChangeRing(C,AlgebraicClosure(Rationals()))); IdentifyGroup($1);
\(\mathrm{Aut}(X_{\overline{\Q}})\)\(\simeq\) \(V_4 \) (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 everywhere.

magma: [C![-2,5,1],C![1,-1,0],C![1,0,0],C![2,-5,1]];

All rational points: (-2 : 5 : 1), (1 : -1 : 0), (1 : 0 : 0), (2 : -5 : 1)

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

Number of rational Weierstrass points: \(2\)

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

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

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

Torsion: \(\Z/{12}\Z\)

2-torsion field: 4.0.1568.1

Sato-Tate group

\(\mathrm{ST}\)\(\simeq\) $N(G_{1,3})$
\(\mathrm{ST}^0\)\(\simeq\) \(\mathrm{U}(1)\times\mathrm{SU}(2)\)

Decomposition

Splits over \(\Q\)

Decomposes up to isogeny as the product of the non-isogenous elliptic curves:
  Elliptic curve 14.a4
  Elliptic curve 32.a2

Endomorphisms

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

Endomorphism ring over \(\Q\):
\(\End (J_{})\)\(\simeq\)an order of index \(2\) in \(\Z \times \Z\)
\(\End (J_{}) \otimes \Q \)\(\simeq\)\(\Q\) \(\times\) \(\Q\)
\(\End (J_{}) \otimes \R\)\(\simeq\) \(\R \times \R\)

Smallest field over which all endomorphisms are defined:
Galois number field \(K = \Q (a) \simeq \) \(\Q(\sqrt{-1}) \) with defining polynomial \(x^{2} + 1\)

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

Endomorphism ring over \(\overline{\Q}\):
\(\End (J_{\overline{\Q}})\)\(\simeq\)an order of index \(8\) in \(\Z \times \Z [\sqrt{-1}]\)
\(\End (J_{\overline{\Q}}) \otimes \Q \)\(\simeq\)\(\Q\) \(\times\) \(\Q(\sqrt{-1}) \)
\(\End (J_{\overline{\Q}}) \otimes \R\)\(\simeq\) \(\R \times \C\)