# Properties

 Label 2.2.13.1-676.1-b2 Base field $$\Q(\sqrt{13})$$ Conductor norm $$676$$ CM no Base change yes Q-curve yes Torsion order $$1$$ Rank $$1$$

# Related objects

Show commands: Magma / PariGP / SageMath

## Base field$$\Q(\sqrt{13})$$

Generator $$a$$, with minimal polynomial $$x^{2} - x - 3$$; class number $$1$$.

sage: R.<x> = PolynomialRing(QQ); K.<a> = NumberField(R([-3, -1, 1]))

gp: K = nfinit(Polrev([-3, -1, 1]));

magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![-3, -1, 1]);

## Weierstrass equation

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

gp: E = ellinit([Polrev([1,0]),Polrev([-1,0]),Polrev([0,0]),Polrev([1,0]),Polrev([1,0])], K);

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

This is a global minimal model.

sage: E.is_global_minimal_model()

## Invariants

 Conductor: $$(26)$$ = $$(2)\cdot(-2a+1)^{2}$$ sage: E.conductor()  gp: ellglobalred(E)[1]  magma: Conductor(E); Conductor norm: $$676$$ = $$4\cdot13^{2}$$ sage: E.conductor().norm()  gp: idealnorm(ellglobalred(E)[1])  magma: Norm(Conductor(E)); Discriminant: $$(-676)$$ = $$(2)^{2}\cdot(-2a+1)^{4}$$ sage: E.discriminant()  gp: E.disc  magma: Discriminant(E); Discriminant norm: $$456976$$ = $$4^{2}\cdot13^{4}$$ sage: E.discriminant().norm()  gp: norm(E.disc)  magma: Norm(Discriminant(E)); j-invariant: $$\frac{351}{4}$$ 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 $\left(0 : -1 : 1\right)$ Height $$0.16981435127840786675757737391447202240$$ Torsion structure: trivial sage: T = E.torsion_subgroup(); T.invariants()  gp: T = elltors(E); T[2]  magma: T,piT := TorsionSubgroup(E); Invariants(T);

## BSD invariants

 Analytic rank: $$1$$ sage: E.rank()  magma: Rank(E); Mordell-Weil rank: $$1$$ Regulator: $$0.16981435127840786675757737391447202240$$ Period: $$14.152515130562803890234604780039206430$$ Tamagawa product: $$2$$  =  $$2\cdot1$$ Torsion order: $$1$$ Leading coefficient: $$2.6662221582690982204781105628666232991$$ 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$$(j)_{-}$$
$$(2)$$ $$4$$ $$2$$ $$I_{2}$$ Split multiplicative $$-1$$ $$1$$ $$2$$ $$2$$
$$(-2a+1)$$ $$13$$ $$1$$ $$IV$$ Additive $$1$$ $$2$$ $$4$$ $$0$$

## Galois Representations

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

prime Image of Galois Representation
$$7$$ 7B.2.1

## Isogenies and isogeny class

This curve has non-trivial cyclic isogenies of degree $$d$$ for $$d=$$ 7.
Its isogeny class 676.1-b consists of curves linked by isogenies of degree 7.

## Base change

This elliptic curve is a $$\Q$$-curve. It is the base change of the following 2 elliptic curves:

Base field Curve
$$\Q$$ 338.c2
$$\Q$$ 338.e2