Properties

Base field 4.4.2777.1
Label 4.4.2777.1-8.2-a3
Conductor \((8,a^{3} - 2 a^{2} - 2 a + 4)\)
Conductor norm \( 8 \)
CM no
base-change no
Q-curve no
Torsion order \( 4 \)
Rank not available

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Base field 4.4.2777.1

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

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

Weierstrass equation

\( y^2 + \left(a^{2} - 2\right) x y = x^{3} + \left(a^{3} - 3 a - 2\right) x^{2} + \left(9 a^{3} - 25 a^{2} + 14 a + 4\right) x - 30 a^{3} + 72 a^{2} + 25 a - 54 \)
magma: E := ChangeRing(EllipticCurve([a^2 - 2, a^3 - 3*a - 2, 0, 9*a^3 - 25*a^2 + 14*a + 4, -30*a^3 + 72*a^2 + 25*a - 54]),K);
sage: E = EllipticCurve(K, [a^2 - 2, a^3 - 3*a - 2, 0, 9*a^3 - 25*a^2 + 14*a + 4, -30*a^3 + 72*a^2 + 25*a - 54])
gp (2.8): E = ellinit([a^2 - 2, a^3 - 3*a - 2, 0, 9*a^3 - 25*a^2 + 14*a + 4, -30*a^3 + 72*a^2 + 25*a - 54],K)

This is a global minimal model.

sage: E.is_global_minimal_model()

Invariants

\(\mathfrak{N} \) = \((8,a^{3} - 2 a^{2} - 2 a + 4)\) = \( \left(-a\right)^{3} \)
magma: Conductor(E);
sage: E.conductor()
\(N(\mathfrak{N}) \) = \( 8 \) = \( 2^{3} \)
magma: Norm(Conductor(E));
sage: E.conductor().norm()
\(\mathfrak{D}\) = \((256,a + 234,a^{3} - a^{2} - 3 a + 142,a^{2} - a + 50)\) = \( \left(-a\right)^{8} \)
magma: Discriminant(E);
sage: E.discriminant()
gp (2.8): E.disc
\(N(\mathfrak{D})\) = \( 256 \) = \( 2^{8} \)
magma: Norm(Discriminant(E));
sage: E.discriminant().norm()
gp (2.8): norm(E.disc)
\(j\) = \( -2732527394 a^{3} + 1558959970 a^{2} + 13692770763 a + 7728253510 \)
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: $\left(-2 a^{2} + 4 a : -a^{3} + 2 a^{2} + 3 a - 2 : 1\right)$,$\left(-\frac{1}{4} a^{3} + a^{2} - \frac{11}{4} a + \frac{5}{2} : \frac{5}{4} a^{3} - \frac{15}{8} a^{2} - \frac{21}{8} a + \frac{13}{4} : 1\right)$
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\((j)_{-}\)
\( \left(-a\right) \) \(2\) \(2\) \(I_{1}^*\) Additive \(1\) \(3\) \(8\) \(0\)

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 8.2-a 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.