Properties

Label 2.0.120.1-605.2-a1
Base field \(\Q(\sqrt{-30}) \)
Conductor norm \( 605 \)
CM no
Base change yes
Q-curve yes
Torsion order \( 2 \)
Rank \( 1 \)

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Base field \(\Q(\sqrt{-30}) \)

Generator \(a\), with minimal polynomial \( x^{2} + 30 \); class number \(4\).

Copy content comment:Define the base number field
 
Copy content sage:R.<x> = PolynomialRing(QQ); K.<a> = NumberField(R([30, 0, 1]))
 
Copy content gp:K = nfinit(Polrev([30, 0, 1]));
 
Copy content magma:R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![30, 0, 1]);
 
Copy content oscar:Qx, x = polynomial_ring(QQ); K, a = number_field(Qx([30, 0, 1]))
 

Weierstrass equation

\({y}^2+{x}{y}+{y}={x}^3-{x}^2+7{x}-8\)
Copy content comment:Define the curve
 
Copy content sage:E = EllipticCurve([K([1,0]),K([-1,0]),K([1,0]),K([7,0]),K([-8,0])])
 
Copy content gp:E = ellinit([Polrev([1,0]),Polrev([-1,0]),Polrev([1,0]),Polrev([7,0]),Polrev([-8,0])], K);
 
Copy content magma:E := EllipticCurve([K![1,0],K![-1,0],K![1,0],K![7,0],K![-8,0]]);
 
Copy content oscar:E = elliptic_curve([K([1,0]),K([-1,0]),K([1,0]),K([7,0]),K([-8,0])])
 

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

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

Mordell-Weil generators

$P$$\hat{h}(P)$Order
$\left(10 : -37 : 1\right)$$1.3186317800226628430785586238185946618$$\infty$
$\left(1 : -1 : 1\right)$$0$$2$

Invariants

Conductor: $\frak{N}$ = \((55,11a)\) = \((5,a)\cdot(11,a+5)\cdot(11,a+6)\)
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: $N(\frak{N})$ = \( 605 \) = \(5\cdot11\cdot11\)
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: $\Delta$ = $40095$
Discriminant ideal: $(\Delta)$ = \((40095)\) = \((3,a)^{12}\cdot(5,a)^{2}\cdot(11,a+5)\cdot(11,a+6)\)
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: $N(\Delta)$ = \( 1607609025 \) = \(3^{12}\cdot5^{2}\cdot11\cdot11\)
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: $\frak{D}_{\mathrm{min}}$ = \((55)\) = \((5,a)^{2}\cdot(11,a+5)\cdot(11,a+6)\)
Minimal discriminant norm: $N(\frak{D}_{\mathrm{min}})$ = \( 3025 \) = \(5^{2}\cdot11\cdot11\)
j-invariant: $j$ = \( \frac{59319}{55} \)
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: $r_{\mathrm{an}}$= \( 1 \)
Copy content comment:Compute the Mordell-Weil rank
 
Copy content sage:E.rank()
 
Copy content magma:Rank(E);
 
Mordell-Weil rank: $r$ = \(1\)
Regulator: $\mathrm{Reg}(E/K)$ \( 1.3186317800226628430785586238185946618 \)
Néron-Tate Regulator: $\mathrm{Reg}_{\mathrm{NT}}(E/K)$ \( 2.637263560045325686157117247637189324 \)
Global period: $\Omega(E/K)$ \( 14.16497688765232383441274891462767130 \)
Tamagawa product: $\prod_{\frak{p}}c_{\frak{p}}$= \( 2 \)  =  \(1\cdot2\cdot1\cdot1\)
Torsion order: $\#E(K)_{\mathrm{tor}}$= \(2\)
Special value: $L^{(r)}(E/K,1)/r!$ \( 1.7050958036513484365477373959402136843 \)
Analytic order of Ш: Ш${}_{\mathrm{an}}$= \( 1 \) (rounded)

BSD formula

$$\begin{aligned}1.705095804 \approx L'(E/K,1) & \overset{?}{=} \frac{ \# Ш(E/K) \cdot \Omega(E/K) \cdot \mathrm{Reg}_{\mathrm{NT}}(E/K) \cdot \prod_{\mathfrak{p}} c_{\mathfrak{p}} } { \#E(K)_{\mathrm{tor}}^2 \cdot \left|d_K\right|^{1/2} } \\ & \approx \frac{ 1 \cdot 14.164977 \cdot 2.637264 \cdot 2 } { {2^2 \cdot 10.954451} } \\ & \approx 1.705095804 \end{aligned}$$

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 \(\mathrm{ord}_{\mathfrak{p}}(\mathfrak{N}\)) \(\mathrm{ord}_{\mathfrak{p}}(\mathfrak{D}_{\mathrm{min}}\)) \(\mathrm{ord}_{\mathfrak{p}}(\mathrm{den}(j))\)
\((3,a)\) \(3\) \(1\) \(I_0\) Good \(1\) \(0\) \(0\) \(0\)
\((5,a)\) \(5\) \(2\) \(I_{2}\) Non-split multiplicative \(1\) \(1\) \(2\) \(2\)
\((11,a+5)\) \(11\) \(1\) \(I_{1}\) Split multiplicative \(-1\) \(1\) \(1\) \(1\)
\((11,a+6)\) \(11\) \(1\) \(I_{1}\) 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
\(2\) 2Cs

Isogenies and isogeny class

This curve has non-trivial cyclic isogenies of degree \(d\) for \(d=\) 2 and 4.
Its isogeny class 605.2-a consists of curves linked by isogenies of degrees dividing 4.

Base change

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

Base field Curve
\(\Q\) 495.a4
\(\Q\) 17600.bu4