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Properties

Label 6845.a.6845.1
Conductor 6845
Discriminant 6845
Sato-Tate group $G_{3,3}$
\(\End(J_{\overline{\Q}}) \otimes \R\) \(\R \times \R\)
\(\End(J_{\overline{\Q}}) \otimes \Q\) \(\Q \times \Q\)
\(\overline{\Q}\)-simple no
\(\mathrm{GL}_2\)-type yes

Related objects

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Show commands for: Magma / SageMath

Minimal equation

magma: R<x> := PolynomialRing(Rationals()); C := HyperellipticCurve(R![-5, -15, -16, -7, 0, 1], R![0, 0, 0, 1]);
 
sage: R.<x> = PolynomialRing(QQ); C = HyperellipticCurve(R([-5, -15, -16, -7, 0, 1]), R([0, 0, 0, 1]))
 

$y^2 + x^3y = x^5 - 7x^3 - 16x^2 - 15x - 5$

Invariants

magma: Conductor(LSeries(C)); Factorization($1);
 
\( N \)  =  \( 6845 \)  =  \( 5 \cdot 37^{2} \)
magma: Discriminant(C); Factorization(Integers()!$1);
 
\( \Delta \)  =  \(6845\)  =  \( 5 \cdot 37^{2} \)

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);
 

\( I_2 \)  =  \(-96\)  =  \( -1 \cdot 2^{5} \cdot 3 \)
\( I_4 \)  =  \(13632\)  =  \( 2^{6} \cdot 3 \cdot 71 \)
\( I_6 \)  =  \(900096\)  =  \( 2^{10} \cdot 3 \cdot 293 \)
\( I_{10} \)  =  \(28037120\)  =  \( 2^{12} \cdot 5 \cdot 37^{2} \)
\( J_2 \)  =  \(-12\)  =  \( -1 \cdot 2^{2} \cdot 3 \)
\( J_4 \)  =  \(-136\)  =  \( -1 \cdot 2^{3} \cdot 17 \)
\( J_6 \)  =  \(-2040\)  =  \( -1 \cdot 2^{3} \cdot 3 \cdot 5 \cdot 17 \)
\( J_8 \)  =  \(1496\)  =  \( 2^{3} \cdot 11 \cdot 17 \)
\( J_{10} \)  =  \(6845\)  =  \( 5 \cdot 37^{2} \)
\( g_1 \)  =  \(-248832/6845\)
\( g_2 \)  =  \(235008/6845\)
\( g_3 \)  =  \(-58752/1369\)
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![-3,7,4],C![-3,20,4],C![-2,3,1],C![-2,5,1],C![-1,0,1],C![-1,1,1],C![1,-1,0],C![1,0,0],C![3,-20,1],C![3,-7,1]];
 

Known rational points: (-3 : 7 : 4), (-3 : 20 : 4), (-2 : 3 : 1), (-2 : 5 : 1), (-1 : 0 : 1), (-1 : 1 : 1), (1 : -1 : 0), (1 : 0 : 0), (3 : -20 : 1), (3 : -7 : 1)

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

Number of rational Weierstrass points: \(0\)

Invariants of the Jacobian:

Analytic rank*: \(2\)

magma: TwoSelmerGroup(Jacobian(C)); NumberOfGenerators($1);
 

2-Selmer rank: \(2\)

magma: HasSquareSha(Jacobian(C));
 

Order of Ш*: square

Regulator: 0.0225460532558

Real period: 14.663072639084885112400475129

Tamagawa numbers: 1 (p = 5), 1 (p = 37)

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

Torsion: \(\mathrm{trivial}\)

2-torsion field: 6.2.438080.1

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 37.a1
  Elliptic curve 185.b1

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 \(\Q\).