Properties

Label 4.4.18625.1-20.1-d2
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

\({y}^2+a{x}{y}+{y}={x}^{3}+\left(-\frac{1}{6}a^{3}+a^{2}+\frac{4}{3}a-\frac{43}{6}\right){x}^{2}+\left(\frac{5}{6}a^{3}-\frac{47}{3}a-\frac{73}{6}\right){x}-\frac{21}{2}a^{3}-19a^{2}+84a+\frac{275}{2}\)
sage: E = EllipticCurve([K([0,1,0,0]),K([-43/6,4/3,1,-1/6]),K([1,0,0,0]),K([-73/6,-47/3,0,5/6]),K([275/2,84,-19,-21/2])])
 
gp: E = ellinit([Polrev([0,1,0,0]),Polrev([-43/6,4/3,1,-1/6]),Polrev([1,0,0,0]),Polrev([-73/6,-47/3,0,5/6]),Polrev([275/2,84,-19,-21/2])], K);
 
magma: E := EllipticCurve([K![0,1,0,0],K![-43/6,4/3,1,-1/6],K![1,0,0,0],K![-73/6,-47/3,0,5/6],K![275/2,84,-19,-21/2]]);
 

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: \((4a^3+a^2-40a-17)\) = \((-a+3)^{4}\cdot(1/2a^3+a^2-5a-21/2)^{2}\)
sage: E.discriminant()
 
gp: E.disc
 
magma: Discriminant(E);
 
Discriminant norm: \( 6400 \) = \(4^{4}\cdot5^{2}\)
sage: E.discriminant().norm()
 
gp: norm(E.disc)
 
magma: Norm(Discriminant(E));
 
j-invariant: \( \frac{1346657}{240} a^{3} + \frac{1161901}{80} a^{2} - \frac{1362329}{48} a - \frac{3661819}{60} \)
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 $\left(2 a + 5 : \frac{19}{6} a^{3} + 5 a^{2} - \frac{88}{3} a - \frac{281}{6} : 1\right)$
Height \(0.091126116807800864797208893422799791837\)
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: $\left(-\frac{1}{4} a^{3} - a^{2} + \frac{9}{4} a + 7 : \frac{5}{8} a^{3} + \frac{5}{8} a^{2} - \frac{37}{8} a - \frac{45}{8} : 1\right)$
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: \( 0.091126116807800864797208893422799791837 \)
Period: \( 923.35384925410346127231605022803516175 \)
Tamagawa product: \( 4 \)  =  \(2\cdot2\)
Torsion order: \(2\)
Leading coefficient: \( 2.46616925103507 \)
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\((j)_{-}\)
\((-a+3)\) \(4\) \(2\) \(I_{4}\) Non-split multiplicative \(1\) \(1\) \(4\) \(4\)
\((1/2a^3+a^2-5a-21/2)\) \(5\) \(2\) \(I_{2}\) Split multiplicative \(-1\) \(1\) \(2\) \(2\)

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-d 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.