Properties

Label 2.0.516.1-98.2-d2
Base field \(\Q(\sqrt{-129}) \)
Conductor norm \( 98 \)
CM no
Base change yes
Q-curve yes
Torsion order \( 2 \)
Rank \( 2 \)

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Base field \(\Q(\sqrt{-129}) \)

Generator \(a\), with minimal polynomial \( x^{2} + 129 \); class number \(12\).

Copy content comment:Define the base number field
 
Copy content sage:R.<x> = PolynomialRing(QQ); K.<a> = NumberField(R([129, 0, 1]))
 
Copy content gp:K = nfinit(Polrev([129, 0, 1]));
 
Copy content magma:R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![129, 0, 1]);
 
Copy content oscar:Qx, x = polynomial_ring(QQ); K, a = number_field(Qx([129, 0, 1]))
 

Weierstrass equation

\({y}^2+a{x}{y}={x}^3+342{x}-1184\)
Copy content comment:Define the curve
 
Copy content sage:E = EllipticCurve([K([0,1]),K([0,0]),K([0,0]),K([342,0]),K([-1184,0])])
 
Copy content gp:E = ellinit([Polrev([0,1]),Polrev([0,0]),Polrev([0,0]),Polrev([342,0]),Polrev([-1184,0])], K);
 
Copy content magma:E := EllipticCurve([K![0,1],K![0,0],K![0,0],K![342,0],K![-1184,0]]);
 
Copy content oscar:E = elliptic_curve([K([0,1]),K([0,0]),K([0,0]),K([342,0]),K([-1184,0])])
 

This is not a global minimal model: it is minimal at all primes except \((3,a)\). No global minimal model exists.

Copy content comment:Test whether it is a global minimal model
 
Copy content sage:E.is_global_minimal_model()
 

Mordell-Weil group structure

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

Mordell-Weil generators

$P$$\hat{h}(P)$Order
$\left(12 : -6 a + 2 : 1\right)$$0.70155617528104437603827294535073893312$$\infty$
$\left(-\frac{923449}{972} : -\frac{112697107}{52488} a : 1\right)$$13.748613869349245719372881381028539722$$\infty$
$\left(8 : -4 a : 1\right)$$0$$2$

Invariants

Conductor: $\frak{N}$ = \((14,7a+7)\) = \((2,a+1)\cdot(7,a+2)\cdot(7,a+5)\)
Copy content comment:Compute the conductor
 
Copy content sage:E.conductor()
 
Copy content gp:ellglobalred(E)[1]
 
Copy content magma:Conductor(E);
 
Copy content oscar:conductor(E)
 
Conductor norm: $N(\frak{N})$ = \( 98 \) = \(2\cdot7\cdot7\)
Copy content comment:Compute the norm of the conductor
 
Copy content sage:E.conductor().norm()
 
Copy content gp:idealnorm(K, ellglobalred(E)[1])
 
Copy content magma:Norm(Conductor(E));
 
Copy content oscar:norm(conductor(E))
 
Discriminant: $\Delta$ = $20412$
Discriminant ideal: $(\Delta)$ = \((20412)\) = \((2,a+1)^{4}\cdot(3,a)^{12}\cdot(7,a+2)\cdot(7,a+5)\)
Copy content comment:Compute the discriminant
 
Copy content sage:E.discriminant()
 
Copy content gp:E.disc
 
Copy content magma:Discriminant(E);
 
Copy content oscar:discriminant(E)
 
Discriminant norm: $N(\Delta)$ = \( 416649744 \) = \(2^{4}\cdot3^{12}\cdot7\cdot7\)
Copy content comment:Compute the norm of the discriminant
 
Copy content sage:E.discriminant().norm()
 
Copy content gp:norm(E.disc)
 
Copy content magma:Norm(Discriminant(E));
 
Copy content oscar:norm(discriminant(E))
 
Minimal discriminant: $\frak{D}_{\mathrm{min}}$ = \((28)\) = \((2,a+1)^{4}\cdot(7,a+2)\cdot(7,a+5)\)
Minimal discriminant norm: $N(\frak{D}_{\mathrm{min}})$ = \( 784 \) = \(2^{4}\cdot7\cdot7\)
j-invariant: $j$ = \( -\frac{15625}{28} \)
Copy content comment:Compute the j-invariant
 
Copy content sage:E.j_invariant()
 
Copy content gp:E.j
 
Copy content magma:jInvariant(E);
 
Copy content oscar:j_invariant(E)
 
Endomorphism ring: $\mathrm{End}(E)$ = \(\Z\)   
Geometric endomorphism ring: $\mathrm{End}(E_{\overline{\Q}})$ = \(\Z\)    (no potential complex multiplication)
Copy content comment:Test for Complex Multiplication
 
Copy content sage:E.has_cm(), E.cm_discriminant()
 
Copy content magma:HasComplexMultiplication(E);
 
Sato-Tate group: $\mathrm{ST}(E)$ = $\mathrm{SU}(2)$

BSD invariants

Analytic rank: $r_{\mathrm{an}}$= \( 2 \)
Copy content comment:Compute the Mordell-Weil rank
 
Copy content sage:E.rank()
 
Copy content magma:Rank(E);
 
Mordell-Weil rank: $r$ = \(2\)
Regulator: $\mathrm{Reg}(E/K)$ \( 9.6454249615965771723207662969449374797 \)
Néron-Tate Regulator: $\mathrm{Reg}_{\mathrm{NT}}(E/K)$ \( 38.581699846386308689283065187779749919 \)
Global period: $\Omega(E/K)$ \( 31.515016866984194237974259626482832830 \)
Tamagawa product: $\prod_{\frak{p}}c_{\frak{p}}$= \( 4 \)  =  \(2^{2}\cdot1\cdot1\cdot1\)
Torsion order: $\#E(K)_{\mathrm{tor}}$= \(2\)
Special value: $L^{(r)}(E/K,1)/r!$ \( 26.763570729112563690095723452249100552 \)
Analytic order of Ш: Ш${}_{\mathrm{an}}$= \( 1 \) (rounded)

BSD formula

$$\begin{aligned}26.763570729 \approx L^{(2)}(E/K,1)/2! & \overset{?}{=} \frac{ \# ะจ(E/K) \cdot \Omega(E/K) \cdot \mathrm{Reg}_{\mathrm{NT}}(E/K) \cdot \prod_{\mathfrak{p}} c_{\mathfrak{p}} } { \#E(K)_{\mathrm{tor}}^2 \cdot \left|d_K\right|^{1/2} } \\ & \approx \frac{ 1 \cdot 15.757508 \cdot 38.581700 \cdot 4 } { {2^2 \cdot 22.715633} } \\ & \approx 26.763570729 \end{aligned}$$

Local data at primes of bad reduction

Copy content comment:Compute the local reduction data at primes of bad reduction
 
Copy content sage:E.local_data()
 
Copy content magma:LocalInformation(E);
 

This elliptic curve is semistable. There are 3 primes $\frak{p}$ of bad reduction. Primes of good reduction for the curve but which divide the discriminant of the model above (if any) are included.

$\mathfrak{p}$ $N(\mathfrak{p})$ Tamagawa number Kodaira symbol Reduction type Root number \(\mathrm{ord}_{\mathfrak{p}}(\mathfrak{N}\)) \(\mathrm{ord}_{\mathfrak{p}}(\mathfrak{D}_{\mathrm{min}}\)) \(\mathrm{ord}_{\mathfrak{p}}(\mathrm{den}(j))\)
\((2,a+1)\) \(2\) \(4\) \(I_{4}\) Split multiplicative \(-1\) \(1\) \(4\) \(4\)
\((3,a)\) \(3\) \(1\) \(I_0\) Good \(1\) \(0\) \(0\) \(0\)
\((7,a+2)\) \(7\) \(1\) \(I_{1}\) Non-split multiplicative \(1\) \(1\) \(1\) \(1\)
\((7,a+5)\) \(7\) \(1\) \(I_{1}\) Non-split multiplicative \(1\) \(1\) \(1\) \(1\)

Galois Representations

The mod \( p \) Galois Representation has maximal image for all primes \( p < 1000 \) except those listed.

prime Image of Galois Representation
\(2\) 2B
\(3\) 3Cs

Isogenies and isogeny class

This curve has non-trivial cyclic isogenies of degree \(d\) for \(d=\) 2, 3, 6, 9 and 18.
Its isogeny class 98.2-d consists of curves linked by isogenies of degrees dividing 18.

Base change

This elliptic curve is a \(\Q\)-curve. It is the base change of the following 2 elliptic curves:

Base field Curve
\(\Q\) 1008.h5
\(\Q\) 25886.d5