Properties

Label 295.a.295.2
Conductor 295
Discriminant -295
Mordell-Weil group \(\Z/{2}\Z\)
Sato-Tate group $\mathrm{USp}(4)$
\(\End(J_{\overline{\Q}}) \otimes \R\) \(\R\)
\(\End(J_{\overline{\Q}}) \otimes \Q\) \(\Q\)
\(\overline{\Q}\)-simple yes
\(\mathrm{GL}_2\)-type no

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Minimal equation

Minimal equation

Simplified equation

$y^2 + (x^2 + x + 1)y = x^5 - 40x^3 + 22x^2 + 389x - 608$ (homogenize, simplify)
$y^2 + (x^2z + xz^2 + z^3)y = x^5z - 40x^3z^3 + 22x^2z^4 + 389xz^5 - 608z^6$ (dehomogenize, simplify)
$y^2 = 4x^5 + x^4 - 158x^3 + 91x^2 + 1558x - 2431$ (minimize, homogenize)

sage: R.<x> = PolynomialRing(QQ); C = HyperellipticCurve(R([-608, 389, 22, -40, 0, 1]), R([1, 1, 1]));
 
magma: R<x> := PolynomialRing(Rationals()); C := HyperellipticCurve(R![-608, 389, 22, -40, 0, 1], R![1, 1, 1]);
 
sage: X = HyperellipticCurve(R([-2431, 1558, 91, -158, 1, 4]))
 
magma: X,pi:= SimplifiedModel(C);
 

Invariants

Conductor: \( N \)  =  \(295\) = \( 5 \cdot 59 \)
magma: Conductor(LSeries(C)); Factorization($1);
 
Discriminant: \( \Delta \)  =  \(-295\) = \( - 5 \cdot 59 \)
magma: Discriminant(C); Factorization(Integers()!$1);
 

Igusa-Clebsch invariants

Igusa invariants

G2 invariants

\( I_2 \)  = \(397608\) =  \( 2^{3} \cdot 3 \cdot 16567 \)
\( I_4 \)  = \(1223228004\) =  \( 2^{2} \cdot 3 \cdot 29 \cdot 73 \cdot 179 \cdot 269 \)
\( I_6 \)  = \(147861032449512\) =  \( 2^{3} \cdot 3 \cdot 67 \cdot 101 \cdot 13963 \cdot 65203 \)
\( I_{10} \)  = \(-1208320\) =  \( - 2^{12} \cdot 5 \cdot 59 \)
\( J_2 \)  = \(49701\) =  \( 3 \cdot 16567 \)
\( J_4 \)  = \(90182600\) =  \( 2^{3} \cdot 5^{2} \cdot 450913 \)
\( J_6 \)  = \(203402032096\) =  \( 2^{5} \cdot 31069 \cdot 204587 \)
\( J_8 \)  = \(494095763610824\) =  \( 2^{3} \cdot 31 \cdot 1992321627463 \)
\( J_{10} \)  = \(-295\) =  \( - 5 \cdot 59 \)
\( g_1 \)  = \(-303267334973269931148501/295\)
\( g_2 \)  = \(-2214359494206283568520/59\)
\( g_3 \)  = \(-502441543825401014496/295\)

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: \((1 : 0 : 0)\)

magma: [C![1,0,0]];
 

Number of rational Weierstrass points: \(1\)

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

magma: MordellWeilGroupGenus2(Jacobian(C));
 

Generator $D_0$ Height Order
\(D_0 - 2 \cdot(1 : 0 : 0)\) \(x^2 - 7xz + 11z^2\) \(=\) \(0,\) \(y\) \(=\) \(-4xz^2 + 5z^3\) \(0\) \(2\)

2-torsion field: 6.2.435125.1

BSD invariants

Hasse-Weil conjecture: unverified
Analytic rank: \(0\)
Mordell-Weil rank: \(0\)
2-Selmer rank:\(1\)
Regulator: \( 1 \)
Real period: \( 0.597073 \)
Tamagawa product: \( 1 \)
Torsion order:\( 2 \)
Leading coefficient: \( 0.149268 \)
Analytic order of Ш: \( 1 \)   (rounded)
Order of Ш:square

Local invariants

Prime ord(\(N\)) ord(\(\Delta\)) Tamagawa L-factor
\(5\) \(1\) \(1\) \(1\) \(( 1 + T )( 1 + T + 5 T^{2} )\)
\(59\) \(1\) \(1\) \(1\) \(( 1 + T )( 1 - 4 T + 59 T^{2} )\)

Sato-Tate group

\(\mathrm{ST}\)\(\simeq\) $\mathrm{USp}(4)$
\(\mathrm{ST}^0\)\(\simeq\) \(\mathrm{USp}(4)\)

Decomposition of the Jacobian

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

Endomorphisms of the Jacobian

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

Endomorphism ring over \(\Q\):

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

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