Properties

Base field 4.4.9909.1
Label 4.4.9909.1-21.1-d4
Conductor \((21,-a^{2} + 2 a + 3)\)
Conductor norm \( 21 \)
CM no
base-change no
Q-curve no
Torsion order \( 4 \)
Rank not available

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Base field 4.4.9909.1

Generator \(a\), with minimal polynomial \( x^{4} - 6 x^{2} - 3 x + 3 \); class number \(1\).

magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![3, -3, -6, 0, 1]);
 
sage: x = polygen(QQ); K.<a> = NumberField(x^4 - 6*x^2 - 3*x + 3)
 
gp (2.8): K = nfinit(a^4 - 6*a^2 - 3*a + 3);
 

Weierstrass equation

\( y^2 + \left(a^{3} - a^{2} - 3 a + 2\right) x y + \left(a + 1\right) y = x^{3} + \left(a^{3} - a^{2} - 5 a\right) x^{2} + \left(-34 a^{3} + 6 a^{2} + 144 a - 69\right) x - 240 a^{3} + 410 a^{2} + 1244 a - 706 \)
magma: E := ChangeRing(EllipticCurve([a^3 - a^2 - 3*a + 2, a^3 - a^2 - 5*a, a + 1, -34*a^3 + 6*a^2 + 144*a - 69, -240*a^3 + 410*a^2 + 1244*a - 706]),K);
 
sage: E = EllipticCurve(K, [a^3 - a^2 - 3*a + 2, a^3 - a^2 - 5*a, a + 1, -34*a^3 + 6*a^2 + 144*a - 69, -240*a^3 + 410*a^2 + 1244*a - 706])
 
gp (2.8): E = ellinit([a^3 - a^2 - 3*a + 2, a^3 - a^2 - 5*a, a + 1, -34*a^3 + 6*a^2 + 144*a - 69, -240*a^3 + 410*a^2 + 1244*a - 706],K)
 

This is a global minimal model.

sage: E.is_global_minimal_model()
 

Invariants

\(\mathfrak{N} \) = \((21,-a^{2} + 2 a + 3)\) = \( \left(-a^{3} + a^{2} + 4 a\right) \cdot \left(a^{3} - a^{2} - 4 a + 1\right) \)
magma: Conductor(E);
 
sage: E.conductor()
 
\(N(\mathfrak{N}) \) = \( 21 \) = \( 3 \cdot 7 \)
magma: Norm(Conductor(E));
 
sage: E.conductor().norm()
 
\(\mathfrak{D}\) = \((99698791708803,3 a + 61989144061689,a^{3} - a^{2} - 3 a + 89288439486216,a^{2} + 26250313717206)\) = \( \left(-a^{3} + a^{2} + 4 a\right)^{2} \cdot \left(a^{3} - a^{2} - 4 a + 1\right)^{16} \)
magma: Discriminant(E);
 
sage: E.discriminant()
 
gp (2.8): E.disc
 
\(N(\mathfrak{D})\) = \( 299096375126409 \) = \( 3^{2} \cdot 7^{16} \)
magma: Norm(Discriminant(E));
 
sage: E.discriminant().norm()
 
gp (2.8): norm(E.disc)
 
\(j\) = \( \frac{3075730896093395126238965002}{99698791708803} a^{3} - \frac{3714007662409537173380188813}{99698791708803} a^{2} - \frac{4656548508714567651606714255}{33232930569601} a + \frac{2547146210989604914629326570}{33232930569601} \)
magma: jInvariant(E);
 
sage: E.j_invariant()
 
gp (2.8): E.j
 
\( \text{End} (E) \) = \(\Z\)   (no Complex Multiplication )
magma: HasComplexMultiplication(E);
 
sage: E.has_cm(), E.cm_discriminant()
 
\( \text{ST} (E) \) = $\mathrm{SU}(2)$

Mordell-Weil group

Rank not available.
magma: Rank(E);
 
sage: E.rank()
 
magma: Generators(E); // includes torsion
 
sage: E.gens()
 

Regulator: not available

magma: Regulator(Generators(E));
 
sage: E.regulator_of_points(E.gens())
 

Torsion subgroup

Structure: \(\Z/2\Z\times\Z/2\Z\)
magma: TorsionSubgroup(E);
 
sage: E.torsion_subgroup().gens()
 
gp (2.8): elltors(E)[2]
 
magma: Order(TorsionSubgroup(E));
 
sage: E.torsion_order()
 
gp (2.8): elltors(E)[1]
 
Generators: $\left(2 a^{3} - a^{2} - 10 a + 7 : -6 a^{3} + 6 a^{2} + 20 a - 12 : 1\right)$,$\left(-\frac{5}{4} a^{3} - \frac{3}{2} a^{2} + \frac{23}{4} a - \frac{9}{4} : \frac{45}{8} a^{3} - 3 a^{2} - \frac{61}{4} a + 7 : 1\right)$
magma: [f(P): P in Generators(T)] where T,f:=TorsionSubgroup(E);
 
sage: E.torsion_subgroup().gens()
 
gp (2.8): elltors(E)[3]
 

Local data at primes of bad reduction

magma: LocalInformation(E);
 
sage: E.local_data()
 
prime Norm Tamagawa number Kodaira symbol Reduction type Root number ord(\(\mathfrak{N}\)) ord(\(\mathfrak{D}\)) ord\((j)_{-}\)
\( \left(-a^{3} + a^{2} + 4 a\right) \) \(3\) \(2\) \(I_{2}\) Split multiplicative \(-1\) \(1\) \(2\) \(2\)
\( \left(a^{3} - a^{2} - 4 a + 1\right) \) \(7\) \(2\) \(I_{16}\) Non-split multiplicative \(1\) \(1\) \(16\) \(16\)

Galois Representations

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

prime Image of Galois Representation
\(2\) 2Cs

Isogenies and isogeny class

This curve has non-trivial cyclic isogenies of degree \(d\) for \(d=\) 2 and 4.
Its isogeny class 21.1-d 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.