Properties

Label 2.2.217.1-28.1-a5
Base field \(\Q(\sqrt{217}) \)
Conductor norm \( 28 \)
CM no
Base change yes
Q-curve yes
Torsion order \( 2 \)
Rank \( 1 \)

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Base field \(\Q(\sqrt{217}) \)

Generator \(a\), with minimal polynomial \( x^{2} - x - 54 \); class number \(1\).

sage: R.<x> = PolynomialRing(QQ); K.<a> = NumberField(R([-54, -1, 1]))
 
gp: K = nfinit(Polrev([-54, -1, 1]));
 
magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![-54, -1, 1]);
 

Weierstrass equation

\({y}^2+{x}{y}={x}^{3}+{x}^{2}+\left(42214461968990a-332036159139665\right){x}+404920008132587532600a-3184882099359922786381\)
sage: E = EllipticCurve([K([1,0]),K([1,0]),K([0,0]),K([-332036159139665,42214461968990]),K([-3184882099359922786381,404920008132587532600])])
 
gp: E = ellinit([Polrev([1,0]),Polrev([1,0]),Polrev([0,0]),Polrev([-332036159139665,42214461968990]),Polrev([-3184882099359922786381,404920008132587532600])], K);
 
magma: E := EllipticCurve([K![1,0],K![1,0],K![0,0],K![-332036159139665,42214461968990],K![-3184882099359922786381,404920008132587532600]]);
 

This is a global minimal model.

sage: E.is_global_minimal_model()
 

Invariants

Conductor: \((-996a+7834)\) = \((-a+8)\cdot(-a-7)\cdot(-498a+3917)\)
sage: E.conductor()
 
gp: ellglobalred(E)[1]
 
magma: Conductor(E);
 
Conductor norm: \( 28 \) = \(2\cdot2\cdot7\)
sage: E.conductor().norm()
 
gp: idealnorm(ellglobalred(E)[1])
 
magma: Norm(Conductor(E));
 
Discriminant: \((98)\) = \((-a+8)\cdot(-a-7)\cdot(-498a+3917)^{4}\)
sage: E.discriminant()
 
gp: E.disc
 
magma: Discriminant(E);
 
Discriminant norm: \( 9604 \) = \(2\cdot2\cdot7^{4}\)
sage: E.discriminant().norm()
 
gp: norm(E.disc)
 
magma: Norm(Discriminant(E));
 
j-invariant: \( \frac{128787625}{98} \)
sage: E.j_invariant()
 
gp: E.j
 
magma: jInvariant(E);
 
Endomorphism ring: \(\Z\)
Geometric endomorphism ring: \(\Z\) (no potential complex multiplication)
sage: E.has_cm(), E.cm_discriminant()
 
magma: HasComplexMultiplication(E);
 
Sato-Tate group: $\mathrm{SU}(2)$

Mordell-Weil group

Rank: \(1\)
Generator $\left(-\frac{84070036}{27} a + \frac{1983748465}{81} : -\frac{12322283627014}{729} a + \frac{96920428130891}{729} : 1\right)$
Height \(5.4805388654068310989157856117407380908\)
Torsion structure: \(\Z/2\Z\)
sage: T = E.torsion_subgroup(); T.invariants()
 
gp: T = elltors(E); T[2]
 
magma: T,piT := TorsionSubgroup(E); Invariants(T);
 
Torsion generator: $\left(956824 a - \frac{30103445}{4} : -478412 a + \frac{30103445}{8} : 1\right)$
sage: T.gens()
 
gp: T[3]
 
magma: [piT(P) : P in Generators(T)];
 

BSD invariants

Analytic rank: \( 1 \)
sage: E.rank()
 
magma: Rank(E);
 
Mordell-Weil rank: \(1\)
Regulator: \( 5.4805388654068310989157856117407380908 \)
Period: \( 7.0277081059000617705423007125374356141 \)
Tamagawa product: \( 4 \)  =  \(1\cdot1\cdot2^{2}\)
Torsion order: \(2\)
Leading coefficient: \( 5.2292223117389075185416716300836499281 \)
Analytic order of Ш: \( 1 \) (rounded)

Local data at primes of bad reduction

sage: E.local_data()
 
magma: LocalInformation(E);
 
prime Norm Tamagawa number Kodaira symbol Reduction type Root number ord(\(\mathfrak{N}\)) ord(\(\mathfrak{D}\)) ord\((j)_{-}\)
\((-a+8)\) \(2\) \(1\) \(I_{1}\) Non-split multiplicative \(1\) \(1\) \(1\) \(1\)
\((-a-7)\) \(2\) \(1\) \(I_{1}\) Non-split multiplicative \(1\) \(1\) \(1\) \(1\)
\((-498a+3917)\) \(7\) \(4\) \(I_{4}\) Split multiplicative \(-1\) \(1\) \(4\) \(4\)

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
\(3\) 3B

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 28.1-a 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
\(\Q\) 98.a4
\(\Q\) 13454.d4