Properties

Label 3.3.81.1-8.1-a2
Base field \(\Q(\zeta_{9})^+\)
Conductor norm \( 8 \)
CM no
Base change yes
Q-curve yes
Torsion order \( 3 \)
Rank \( 0 \)

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Base field \(\Q(\zeta_{9})^+\)

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

sage: R.<x> = PolynomialRing(QQ); K.<a> = NumberField(R([-1, -3, 0, 1]))
 
gp: K = nfinit(Polrev([-1, -3, 0, 1]));
 
magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![-1, -3, 0, 1]);
 

Weierstrass equation

\({y}^2+a{x}{y}+\left(a^{2}-1\right){y}={x}^{3}-{x}^{2}+\left(125040a^{2}-43189a-360486\right){x}+56242078a^{2}-19527401a-161952511\)
sage: E = EllipticCurve([K([0,1,0]),K([-1,0,0]),K([-1,0,1]),K([-360486,-43189,125040]),K([-161952511,-19527401,56242078])])
 
gp: E = ellinit([Polrev([0,1,0]),Polrev([-1,0,0]),Polrev([-1,0,1]),Polrev([-360486,-43189,125040]),Polrev([-161952511,-19527401,56242078])], K);
 
magma: E := EllipticCurve([K![0,1,0],K![-1,0,0],K![-1,0,1],K![-360486,-43189,125040],K![-161952511,-19527401,56242078]]);
 

This is a global minimal model.

sage: E.is_global_minimal_model()
 

Invariants

Conductor: \((2)\) = \((2)\)
sage: E.conductor()
 
gp: ellglobalred(E)[1]
 
magma: Conductor(E);
 
Conductor norm: \( 8 \) = \(8\)
sage: E.conductor().norm()
 
gp: idealnorm(ellglobalred(E)[1])
 
magma: Norm(Conductor(E));
 
Discriminant: \((-2097152)\) = \((2)^{21}\)
sage: E.discriminant()
 
gp: E.disc
 
magma: Discriminant(E);
 
Discriminant norm: \( -9223372036854775808 \) = \(-8^{21}\)
sage: E.discriminant().norm()
 
gp: norm(E.disc)
 
magma: Norm(Discriminant(E));
 
j-invariant: \( -\frac{1159088625}{2097152} \)
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: \(\Z/3\Z\)
sage: T = E.torsion_subgroup(); T.invariants()
 
gp: T = elltors(E); T[2]
 
magma: T,piT := TorsionSubgroup(E); Invariants(T);
 
Torsion generator: $\left(-\frac{1219}{3} a^{2} + 125 a + \frac{3601}{3} : \frac{33091}{3} a^{2} - \frac{11812}{3} a - \frac{94685}{3} : 1\right)$
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: \( 1.1276992257415772736525574059704960331 \)
Tamagawa product: \( 21 \)
Torsion order: \(3\)
Leading coefficient: \( 0.29236646593300151539140377191827674932 \)
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\((j)_{-}\)
\((2)\) \(8\) \(21\) \(I_{21}\) Split multiplicative \(-1\) \(1\) \(21\) \(21\)

Galois Representations

The mod \( p \) Galois Representation has maximal image for all primes \( p < 1000 \) except those listed.

prime Image of Galois Representation
\(3\) 3B.1.1
\(7\) 7B.1.3

Isogenies and isogeny class

This curve has non-trivial cyclic isogenies of degree \(d\) for \(d=\) 3, 7 and 21.
Its isogeny class 8.1-a consists of curves linked by isogenies of degrees dividing 21.

Base change

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

Base field Curve
\(\Q\) 162.c2