Properties

Label 2.2.205.1-28.2-b3
Base field \(\Q(\sqrt{205}) \)
Conductor norm \( 28 \)
CM no
Base change no
Q-curve no
Torsion order \( 4 \)
Rank \( 2 \)

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Base field \(\Q(\sqrt{205}) \)

Generator \(a\), with minimal polynomial \( x^{2} - x - 51 \); class number \(2\).

sage: R.<x> = PolynomialRing(QQ); K.<a> = NumberField(R([-51, -1, 1]))
 
gp: K = nfinit(Polrev([-51, -1, 1]));
 
magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![-51, -1, 1]);
 

Weierstrass equation

\({y}^2+w{x}{y}+w{y}={x}^3-w{x}^2+\left(-2w-19\right){x}+11w-174\)
sage: E = EllipticCurve([K([0,1]),K([0,-1]),K([0,1]),K([-19,-2]),K([-174,11])])
 
gp: E = ellinit([Polrev([0,1]),Polrev([0,-1]),Polrev([0,1]),Polrev([-19,-2]),Polrev([-174,11])], K);
 
magma: E := EllipticCurve([K![0,1],K![0,-1],K![0,1],K![-19,-2],K![-174,11]]);
 

This is a global minimal model.

sage: E.is_global_minimal_model()
 

Invariants

Conductor: \((14,2a+10)\) = \((2)\cdot(7,a+5)\)
sage: E.conductor()
 
gp: ellglobalred(E)[1]
 
magma: Conductor(E);
 
Conductor norm: \( 28 \) = \(4\cdot7\)
sage: E.conductor().norm()
 
gp: idealnorm(ellglobalred(E)[1])
 
magma: Norm(Conductor(E));
 
Discriminant: \((-1284a+13936)\) = \((2)^{2}\cdot(7,a+5)^{8}\)
sage: E.discriminant()
 
gp: E.disc
 
magma: Discriminant(E);
 
Discriminant norm: \( 92236816 \) = \(4^{2}\cdot7^{8}\)
sage: E.discriminant().norm()
 
gp: norm(E.disc)
 
magma: Norm(Discriminant(E));
 
j-invariant: \( \frac{780348831047775}{23059204} a + \frac{1299078889648623}{5764801} \)
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: \(2\)
Generators $\left(\frac{13}{9} a - \frac{16}{3} : \frac{50}{27} a - \frac{200}{9} : 1\right)$ $\left(\frac{1}{3} a - \frac{68}{9} : \frac{40}{9} a - \frac{505}{27} : 1\right)$
Heights \(2.1402472986621658288241245179362099579\) \(2.6553291318083252600060544984930074555\)
Torsion structure: \(\Z/2\Z\oplus\Z/2\Z\)
sage: T = E.torsion_subgroup(); T.invariants()
 
gp: T = elltors(E); T[2]
 
magma: T,piT := TorsionSubgroup(E); Invariants(T);
 
Torsion generators: $\left(\frac{3}{4} a - \frac{43}{4} : \frac{9}{2} a - \frac{153}{8} : 1\right)$ $\left(-5 : 2 a : 1\right)$
sage: T.gens()
 
gp: T[3]
 
magma: [piT(P) : P in Generators(T)];
 

BSD invariants

Analytic rank: \( 2 \)
sage: E.rank()
 
magma: Rank(E);
 
Mordell-Weil rank: \(2\)
Regulator: \( 5.4587435659360312087544588253619862003 \)
Period: \( 3.9432131433469299769855676139040918823 \)
Tamagawa product: \( 16 \)  =  \(2\cdot2^{3}\)
Torsion order: \(4\)
Leading coefficient: \( 6.0134818783477308128885275361820399861 \)
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 \(-1\) \(1\) \(2\) \(2\)
\((7,a+5)\) \(7\) \(8\) \(I_{8}\) Split multiplicative \(-1\) \(1\) \(8\) \(8\)

Galois Representations

The mod \( p \) Galois Representation has maximal image for all primes \( p < 1000 \) 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.
Its isogeny class 28.2-b consists of curves linked by isogenies of degrees dividing 4.

Base change

This elliptic curve is not a \(\Q\)-curve.

It is not the base change of an elliptic curve defined over any subfield.