Properties

Label 4.4.1125.1-31.1-b1
Base field \(\Q(\zeta_{15})^+\)
Conductor \((a^3+2a^2-3a-3)\)
Conductor norm \( 31 \)
CM no
Base change no
Q-curve no
Torsion order \( 2 \)
Rank \( 0 \)

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Base field \(\Q(\zeta_{15})^+\)

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

sage: R.<x> = PolynomialRing(QQ); K.<a> = NumberField(R([1, 4, -4, -1, 1]))
 
gp: K = nfinit(Pol(Vecrev([1, 4, -4, -1, 1])));
 
magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![1, 4, -4, -1, 1]);
 

Weierstrass equation

\({y}^2+\left(a^{2}-2\right){x}{y}={x}^{3}+\left(-a^{2}+1\right){x}^{2}+\left(-80a^{3}+335a^{2}+315a-1284\right){x}-2177a^{3}+4753a^{2}+8378a-18117\)
sage: E = EllipticCurve([K([-2,0,1,0]),K([1,0,-1,0]),K([0,0,0,0]),K([-1284,315,335,-80]),K([-18117,8378,4753,-2177])])
 
gp: E = ellinit([Pol(Vecrev([-2,0,1,0])),Pol(Vecrev([1,0,-1,0])),Pol(Vecrev([0,0,0,0])),Pol(Vecrev([-1284,315,335,-80])),Pol(Vecrev([-18117,8378,4753,-2177]))], K);
 
magma: E := EllipticCurve([K![-2,0,1,0],K![1,0,-1,0],K![0,0,0,0],K![-1284,315,335,-80],K![-18117,8378,4753,-2177]]);
 

This is a global minimal model.

sage: E.is_global_minimal_model()
 

Invariants

Conductor: \((a^3+2a^2-3a-3)\) = \((a^3+2a^2-3a-3)\)
sage: E.conductor()
 
gp: ellglobalred(E)[1]
 
magma: Conductor(E);
 
Conductor norm: \( 31 \) = \(31\)
sage: E.conductor().norm()
 
gp: idealnorm(ellglobalred(E)[1])
 
magma: Norm(Conductor(E));
 
Discriminant: \((25a^3+26a^2-75a-38)\) = \((a^3+2a^2-3a-3)^{4}\)
sage: E.discriminant()
 
gp: E.disc
 
magma: Discriminant(E);
 
Discriminant norm: \( 923521 \) = \(31^{4}\)
sage: E.discriminant().norm()
 
gp: norm(E.disc)
 
magma: Norm(Discriminant(E));
 
j-invariant: \( \frac{13262138608154212980818020352}{923521} a^{3} - \frac{16034680544860826249617094257}{923521} a^{2} - \frac{49696393399932989894285277456}{923521} a + \frac{63437929696698697519404008684}{923521} \)
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: \(0\)
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: $\left(-\frac{1}{4} a^{3} + 5 a^{2} + a - \frac{87}{4} : -\frac{21}{8} a^{3} + \frac{47}{8} a^{2} + \frac{83}{8} a - \frac{155}{8} : 1\right)$
sage: T.gens()
 
gp: T[3]
 
magma: [piT(P) : P in Generators(T)];
 

BSD invariants

Analytic rank: \( 0 \)
sage: E.rank()
 
magma: Rank(E);
 
Mordell-Weil rank: \(0\)
Regulator: \( 1 \)
Period: \( 2.95942806351483 \)
Tamagawa product: \( 2 \)
Torsion order: \(2\)
Leading coefficient: \( 0.705864781284238 \)
Analytic order of Ш: \( 16 \) (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\((j)_{-}\)
\((a^3+2a^2-3a-3)\) \(31\) \(2\) \(I_{4}\) 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, 4 and 8.
Its isogeny class 31.1-b consists of curves linked by isogenies of degrees dividing 8.

Base change

This curve is not the base change of an elliptic curve defined over \(\Q\). It is not a \(\Q\)-curve.