Properties

Label 4.4.18625.1-20.1-a1
Base field 4.4.18625.1
Conductor norm \( 20 \)
CM no
Base change no
Q-curve no
Torsion order \( 2 \)
Rank \( 1 \)

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Base field 4.4.18625.1

Generator \(a\), with minimal polynomial \( x^{4} - x^{3} - 14 x^{2} + 9 x + 41 \); class number \(1\).

sage: R.<x> = PolynomialRing(QQ); K.<a> = NumberField(R([41, 9, -14, -1, 1]))
 
gp: K = nfinit(Polrev([41, 9, -14, -1, 1]));
 
magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![41, 9, -14, -1, 1]);
 

Weierstrass equation

\({y}^2+\left(\frac{1}{6}a^{3}-\frac{1}{3}a+\frac{1}{6}\right){x}{y}+\left(\frac{1}{6}a^{3}-\frac{1}{3}a+\frac{1}{6}\right){y}={x}^{3}+\left(\frac{1}{6}a^{3}-\frac{7}{3}a+\frac{1}{6}\right){x}^{2}+\left(-\frac{7}{6}a^{3}-a^{2}+\frac{31}{3}a+\frac{71}{6}\right){x}+\frac{413}{6}a^{3}+103a^{2}-\frac{2147}{3}a-\frac{6973}{6}\)
sage: E = EllipticCurve([K([1/6,-1/3,0,1/6]),K([1/6,-7/3,0,1/6]),K([1/6,-1/3,0,1/6]),K([71/6,31/3,-1,-7/6]),K([-6973/6,-2147/3,103,413/6])])
 
gp: E = ellinit([Polrev([1/6,-1/3,0,1/6]),Polrev([1/6,-7/3,0,1/6]),Polrev([1/6,-1/3,0,1/6]),Polrev([71/6,31/3,-1,-7/6]),Polrev([-6973/6,-2147/3,103,413/6])], K);
 
magma: E := EllipticCurve([K![1/6,-1/3,0,1/6],K![1/6,-7/3,0,1/6],K![1/6,-1/3,0,1/6],K![71/6,31/3,-1,-7/6],K![-6973/6,-2147/3,103,413/6]]);
 

This is a global minimal model.

sage: E.is_global_minimal_model()
 

Invariants

Conductor: \((-1/3a^3-a^2+8/3a+20/3)\) = \((-a+3)\cdot(1/2a^3+a^2-5a-21/2)\)
sage: E.conductor()
 
gp: ellglobalred(E)[1]
 
magma: Conductor(E);
 
Conductor norm: \( 20 \) = \(4\cdot5\)
sage: E.conductor().norm()
 
gp: idealnorm(ellglobalred(E)[1])
 
magma: Norm(Conductor(E));
 
Discriminant: \((5/3a^3-55/3a-10/3)\) = \((-a+3)^{2}\cdot(1/2a^3+a^2-5a-21/2)^{4}\)
sage: E.discriminant()
 
gp: E.disc
 
magma: Discriminant(E);
 
Discriminant norm: \( 10000 \) = \(4^{2}\cdot5^{4}\)
sage: E.discriminant().norm()
 
gp: norm(E.disc)
 
magma: Norm(Discriminant(E));
 
j-invariant: \( -\frac{214001}{60} a^{3} + \frac{305383}{20} a^{2} + \frac{54853}{60} a - \frac{124942}{3} \)
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 $\left(-\frac{1}{3} a^{3} - 2 a^{2} + \frac{11}{3} a + \frac{59}{3} : \frac{7}{6} a^{3} - 3 a^{2} - \frac{34}{3} a + \frac{175}{6} : 1\right)$
Height \(0.44530519017323838460176221724783128682\)
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: $\left(-\frac{17}{24} a^{3} - a^{2} + \frac{89}{12} a + \frac{229}{24} : \frac{17}{24} a^{3} + \frac{7}{8} a^{2} - \frac{163}{24} a - \frac{125}{12} : 1\right)$
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: \( 0.44530519017323838460176221724783128682 \)
Period: \( 359.45272989765626493414429238301033409 \)
Tamagawa product: \( 4 \)  =  \(2\cdot2\)
Torsion order: \(2\)
Leading coefficient: \( 4.69149646979632 \)
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\((j)_{-}\)
\((-a+3)\) \(4\) \(2\) \(I_{2}\) Split multiplicative \(-1\) \(1\) \(2\) \(2\)
\((1/2a^3+a^2-5a-21/2)\) \(5\) \(2\) \(I_{4}\) Non-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

Isogenies and isogeny class

This curve has non-trivial cyclic isogenies of degree \(d\) for \(d=\) 2.
Its isogeny class 20.1-a consists of curves linked by isogenies of degree 2.

Base change

This elliptic curve is not a \(\Q\)-curve.

It is not the base change of an elliptic curve defined over any subfield.