# Properties

 Base field $$\Q(\sqrt{-2})$$ Label 2.0.8.1-10000.1-e4 Conductor $$(100)$$ Conductor norm $$10000$$ CM no base-change yes: 1600.o1,400.e1 Q-curve yes Torsion order $$4$$ Rank $$2$$

# Related objects

Show commands for: Magma / SageMath / Pari/GP

## Base field $$\Q(\sqrt{-2})$$

Generator $$a$$, with minimal polynomial $$x^{2} + 2$$; class number $$1$$.

magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![2, 0, 1]);

sage: x = polygen(QQ); K.<a> = NumberField(x^2 + 2)

gp: K = nfinit(a^2 + 2);

## Weierstrass equation

$$y^2 + a x y = x^{3} - x^{2} - 668 x - 6322$$
magma: E := ChangeRing(EllipticCurve([a, -1, 0, -668, -6322]),K);

sage: E = EllipticCurve(K, [a, -1, 0, -668, -6322])

gp: E = ellinit([a, -1, 0, -668, -6322],K)

This is a global minimal model.

sage: E.is_global_minimal_model()

## Invariants

 $$\mathfrak{N}$$ = $$(100)$$ = $$\left(a\right)^{4} \cdot \left(5\right)^{2}$$ magma: Conductor(E);  sage: E.conductor() $$N(\mathfrak{N})$$ = $$10000$$ = $$2^{4} \cdot 25^{2}$$ magma: Norm(Conductor(E));  sage: E.conductor().norm() $$\mathfrak{D}$$ = $$(1250000)$$ = $$\left(a\right)^{8} \cdot \left(5\right)^{7}$$ magma: Discriminant(E);  sage: E.discriminant()  gp: E.disc $$N(\mathfrak{D})$$ = $$1562500000000$$ = $$2^{8} \cdot 25^{7}$$ magma: Norm(Discriminant(E));  sage: E.discriminant().norm()  gp: norm(E.disc) $$j$$ = $$\frac{132304644}{5}$$ magma: jInvariant(E);  sage: E.j_invariant()  gp: 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: $$2$$

magma: Rank(E);

sage: E.rank()

Generators: $\left(-14 : 5 a : 1\right)$, $\left(-\frac{2833}{196} : \frac{2833}{392} a - \frac{1203}{2744} : 1\right)$

magma: gens := [P:P in Generators(E)|Order(P) eq 0]; gens;

sage: gens = E.gens(); gens

Heights: 0.9333935029996572, 6.193893206876932

magma: [Height(P):P in gens];

sage: [P.height() for P in gens]

Regulator: 5.78133967757

magma: Regulator(gens);

sage: E.regulator_of_points(gens)

## Torsion subgroup

Structure: $$\Z/4\Z$$ magma: T,piT := TorsionSubgroup(E); Invariants(T);  sage: T = E.torsion_subgroup(); T.invariants()  gp: T = elltors(E); T[2] $\left(-17 : -4 a : 1\right)$ magma: [piT(P) : P in Generators(T)];  sage: T.gens()  gp: T[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$$(j)_{-}$$
$$\left(a\right)$$ $$2$$ $$2$$ $$I_{0}^*$$ Additive $$-1$$ $$4$$ $$8$$ $$0$$
$$\left(5\right)$$ $$25$$ $$4$$ $$I_{1}^*$$ Additive $$1$$ $$2$$ $$7$$ $$1$$

## Galois Representations

The mod $$p$$ Galois Representation has maximal image for all primes $$p < 1000$$ 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 and 4.
Its isogeny class 10000.1-e consists of curves linked by isogenies of degrees dividing 4.

## Base change

This curve is the base-change of elliptic curves 1600.o1, 400.e1, defined over $$\Q$$, so it is also a $$\Q$$-curve.