Properties

Label 841.a.841.1
Conductor 841
Discriminant -841
Sato-Tate group $G_{3,3}$
\(\End(J_{\overline{\Q}}) \otimes \R\) \(\R \times \R\)
\(\End(J_{\overline{\Q}}) \otimes \Q\) \(\mathrm{RM}\)
\(\overline{\Q}\)-simple yes
\(\mathrm{GL}_2\)-type yes

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The Jacobian of this curve is isogenous to that of the modular curve $X_0(29)$ (which has discriminant $29^5$).

Minimal equation

magma: R<x> := PolynomialRing(Rationals()); C := HyperellipticCurve(R![2, 1, 3, 1, 1], R![0, 1, 1, 1]);
 
sage: R.<x> = PolynomialRing(QQ); C = HyperellipticCurve(R([2, 1, 3, 1, 1]), R([0, 1, 1, 1]))
 

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

Invariants

magma: Conductor(LSeries(C)); Factorization($1);
 
\( N \)  =  \( 841 \)  =  \( 29^{2} \)
magma: Discriminant(C); Factorization(Integers()!$1);
 
\( \Delta \)  =  \(-841\)  =  \( -1 \cdot 29^{2} \)

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);
 

\( I_2 \)  =  \(-2840\)  =  \( -1 \cdot 2^{3} \cdot 5 \cdot 71 \)
\( I_4 \)  =  \(16804\)  =  \( 2^{2} \cdot 4201 \)
\( I_6 \)  =  \(-15791192\)  =  \( -1 \cdot 2^{3} \cdot 61 \cdot 32359 \)
\( I_{10} \)  =  \(-3444736\)  =  \( -1 \cdot 2^{12} \cdot 29^{2} \)
\( J_2 \)  =  \(-355\)  =  \( -1 \cdot 5 \cdot 71 \)
\( J_4 \)  =  \(5076\)  =  \( 2^{2} \cdot 3^{3} \cdot 47 \)
\( J_6 \)  =  \(-93408\)  =  \( -1 \cdot 2^{5} \cdot 3 \cdot 7 \cdot 139 \)
\( J_8 \)  =  \(1848516\)  =  \( 2^{2} \cdot 3 \cdot 154043 \)
\( J_{10} \)  =  \(-841\)  =  \( -1 \cdot 29^{2} \)
\( g_1 \)  =  \(5638216721875/841\)
\( g_2 \)  =  \(227094529500/841\)
\( g_3 \)  =  \(11771743200/841\)
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 everywhere.

magma: [C![1,-1,0],C![1,0,0]];
 

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

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: \(0\)

magma: HasSquareSha(Jacobian(C));
 

Order of Ш*: square

Regulator: 1.0

Real period: 14.284556719258495881238924206

Tamagawa numbers: 1 (p = 29)

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

Torsion: \(\Z/{7}\Z\)

2-torsion field: 6.0.53824.1

Sato-Tate group

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

Decomposition

Simple over \(\overline{\Q}\)

Endomorphisms

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

Endomorphism ring over \(\Q\):
\(\End (J_{})\)\(\simeq\)\(\Z [\sqrt{2}]\)
\(\End (J_{}) \otimes \Q \)\(\simeq\)\(\Q(\sqrt{2}) \)
\(\End (J_{}) \otimes \R\)\(\simeq\) \(\R \times \R\)

All \(\overline{\Q}\)-endomorphisms of the Jacobian are defined over \(\Q\).