# Properties

 Label 2.0.8.1-121.2-a3 Base field $$\Q(\sqrt{-2})$$ Conductor $$(11)$$ Conductor norm $$121$$ CM no Base change yes: 704.c3,11.a3 Q-curve yes Torsion order $$5$$ Rank $$1$$

# Learn more about

Show commands for: Magma / Pari/GP / SageMath

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

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

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

gp: K = nfinit(a^2 + 2);

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

## Weierstrass equation

$$y^2+y=x^{3}-x^{2}$$
sage: E = EllipticCurve(K, [0, -1, 1, 0, 0])

gp: E = ellinit([0, -1, 1, 0, 0],K)

magma: E := ChangeRing(EllipticCurve([0, -1, 1, 0, 0]),K);

This is a global minimal model.

sage: E.is_global_minimal_model()

## Invariants

 Conductor: $$(11)$$ = $$\left(a + 3\right) \cdot \left(a - 3\right)$$ sage: E.conductor()  magma: Conductor(E); Conductor norm: $$121$$ = $$11^{2}$$ sage: E.conductor().norm()  magma: Norm(Conductor(E)); Discriminant: $$(11)$$ = $$\left(a + 3\right) \cdot \left(a - 3\right)$$ sage: E.discriminant()  gp: E.disc  magma: Discriminant(E); Discriminant norm: $$121$$ = $$11^{2}$$ sage: E.discriminant().norm()  gp: norm(E.disc)  magma: Norm(Discriminant(E)); j-invariant: $$-\frac{4096}{11}$$ sage: E.j_invariant()  gp: E.j  magma: jInvariant(E); Endomorphism ring: $$\Z$$ Geometric endomorphism ring: $$\Z$$ (no potential complex multiplication) sage: E.has_cm(), E.cm_discriminant()  magma: HasComplexMultiplication(E); Sato-Tate group: $\mathrm{SU}(2)$

## Mordell-Weil group

 Rank: $$1$$ Generator $\left(-a + 2 : -2 a + 1 : 1\right)$ Height $$0.915095465750466$$ Torsion structure: $$\Z/5\Z$$ sage: T = E.torsion_subgroup(); T.invariants()  gp: T = elltors(E); T[2]  magma: T,piT := TorsionSubgroup(E); Invariants(T); Torsion generator: $\left(0 : -1 : 1\right)$ sage: T.gens()  gp: T[3]  magma: [piT(P) : P in Generators(T)];

## BSD invariants

 Analytic rank: $$1$$ sage: E.rank()  magma: Rank(E); Mordell-Weil rank: $$1$$ Regulator: $$0.915095465750466$$ Period: $$9.25771811727979$$ Tamagawa product: $$1$$  =  $$1\cdot1$$ Torsion order: $$5$$ Leading coefficient: $$0.479231487957330$$ Analytic order of Ш: $$1$$ (rounded)

## Local data at primes of bad reduction

sage: E.local_data()

magma: LocalInformation(E);

prime Norm Tamagawa number Kodaira symbol Reduction type Root number ord($$\mathfrak{N}$$) ord($$\mathfrak{D}$$) ord$$(j)_{-}$$
$$\left(a + 3\right)$$ $$11$$ $$1$$ $$I_{1}$$ Split multiplicative $$-1$$ $$1$$ $$1$$ $$1$$
$$\left(a - 3\right)$$ $$11$$ $$1$$ $$I_{1}$$ Split multiplicative $$-1$$ $$1$$ $$1$$ $$1$$

## Galois Representations

The mod $$p$$ Galois Representation has maximal image for all primes $$p < 1000$$ except those listed.

prime Image of Galois Representation
$$5$$ 5B.1.1

## Isogenies and isogeny class

This curve has non-trivial cyclic isogenies of degree $$d$$ for $$d=$$ 5 and 25.
Its isogeny class 121.2-a consists of curves linked by isogenies of degrees dividing 25.

## Base change

This curve is the base change of elliptic curves 704.c3, 11.a3, defined over $$\Q$$, so it is also a $$\Q$$-curve.