Properties

Base field 4.4.2777.1
Label 4.4.2777.1-16.2-a6
Conductor \((16,-a^{3} + 2 a^{2} + 3 a - 2)\)
Conductor norm \( 16 \)
CM no
base-change no
Q-curve not determined
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

\( y^2 + \left(a^{3} - a^{2} - 3 a + 2\right) x y + a y = x^{3} + \left(-a^{3} + a^{2} + 2 a - 2\right) x^{2} + \left(-4 a^{3} + a^{2} + 6 a - 7\right) x - 9 a^{2} - 7 a + 9 \)
magma: E := ChangeRing(EllipticCurve([a^3 - a^2 - 3*a + 2, -a^3 + a^2 + 2*a - 2, a, -4*a^3 + a^2 + 6*a - 7, -9*a^2 - 7*a + 9]),K);
sage: E = EllipticCurve(K, [a^3 - a^2 - 3*a + 2, -a^3 + a^2 + 2*a - 2, a, -4*a^3 + a^2 + 6*a - 7, -9*a^2 - 7*a + 9])
gp (2.8): E = ellinit([a^3 - a^2 - 3*a + 2, -a^3 + a^2 + 2*a - 2, a, -4*a^3 + a^2 + 6*a - 7, -9*a^2 - 7*a + 9],K)

This is a global minimal model.

sage: E.is_global_minimal_model()

Invariants

\(\mathfrak{N} \) = \((16,-a^{3} + 2 a^{2} + 3 a - 2)\) = \( \left(-a\right)^{4} \)
magma: Conductor(E);
sage: E.conductor()
\(N(\mathfrak{N}) \) = \( 16 \) = \( 2^{4} \)
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 rank and generators

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: $\left(-a^{2} + 3 : -a^{3} + 2 a^{2} + 3 a - 3 : 1\right)$,$\left(a^{3} - 2 a : -a^{3} + a - 1 : 1\right)$
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 ord(\(\mathfrak{N}\)) ord(\(\mathfrak{D}\)) ord\((j)_{-}\)
\( \left(-a\right) \) 2 \(2\) \( I_{0}^* \) Additive 4 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 16.2-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 has not yet been determined whether or not it is a \(\Q\)-curve.