Properties

Base field 4.4.2777.1
Label 4.4.2777.1-16.2-a5
Conductor \((16,-a^{3} + 2 a^{2} + 3 a - 2)\)
Conductor norm \( 16 \)
CM no
base-change no
Q-curve no
Torsion order \( 2 \)
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

\( y^2 + \left(a^{3} - a^{2} - 3 a + 2\right) x y + a y = x^{3} + \left(-a^{3} + a^{2} + 2 a - 2\right) x^{2} + \left(-4 a^{3} + 16 a^{2} - 4 a - 67\right) x - 8 a^{3} + 53 a^{2} - 21 a - 199 \)
magma: E := ChangeRing(EllipticCurve([a^3 - a^2 - 3*a + 2, -a^3 + a^2 + 2*a - 2, a, -4*a^3 + 16*a^2 - 4*a - 67, -8*a^3 + 53*a^2 - 21*a - 199]),K);
sage: E = EllipticCurve(K, [a^3 - a^2 - 3*a + 2, -a^3 + a^2 + 2*a - 2, a, -4*a^3 + 16*a^2 - 4*a - 67, -8*a^3 + 53*a^2 - 21*a - 199])
gp (2.8): E = ellinit([a^3 - a^2 - 3*a + 2, -a^3 + a^2 + 2*a - 2, a, -4*a^3 + 16*a^2 - 4*a - 67, -8*a^3 + 53*a^2 - 21*a - 199],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()
\(\mathfrak{D}\) = \((1024,a + 490,a^{3} - a^{2} - 3 a + 654,a^{2} - a + 50)\) = \( \left(-a\right)^{10} \)
magma: Discriminant(E);
sage: E.discriminant()
gp (2.8): E.disc
\(N(\mathfrak{D})\) = \( 1024 \) = \( 2^{10} \)
magma: Norm(Discriminant(E));
sage: E.discriminant().norm()
gp (2.8): norm(E.disc)
\(j\) = \( -63795770348435003481 a^{3} + 11114208719071878840 a^{2} + 264361023260378305267 a + 154509478780590380994 \)
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: \(\Z/2\Z\)
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]
Generator: $\left(\frac{1}{4} a^{3} + 2 a^{2} - 6 : \frac{7}{4} a^{3} - \frac{17}{4} a^{2} - \frac{59}{8} a + \frac{25}{4} : 1\right)$
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\((j)_{-}\)
\( \left(-a\right) \) \(2\) \(2\) \(I_{2}^*\) Additive \(1\) \(4\) \(10\) \(0\)

Galois Representations

The mod \( p \) Galois Representation has maximal image for all primes \( p \) 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 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 is not a \(\Q\)-curve.