Properties

Label 2.0.228.1-81.1-b2
Base field \(\Q(\sqrt{-57}) \)
Conductor norm \( 81 \)
CM yes (\(-27\))
Base change yes
Q-curve yes
Torsion order \( 1 \)
Rank \( 0 \)

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Base field \(\Q(\sqrt{-57}) \)

Generator \(a\), with minimal polynomial \( x^{2} + 57 \); class number \(4\).

Copy content comment:Define the base number field
 
Copy content sage:R.<x> = PolynomialRing(QQ); K.<a> = NumberField(R([57, 0, 1]))
 
Copy content gp:K = nfinit(Polrev([57, 0, 1]));
 
Copy content magma:R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![57, 0, 1]);
 
Copy content oscar:Qx, x = polynomial_ring(QQ); K, a = number_field(Qx([57, 0, 1]))
 

Weierstrass equation

\({y}^2+{y}={x}^3-270{x}-1708\)
Copy content comment:Define the curve
 
Copy content sage:E = EllipticCurve([K([0,0]),K([0,0]),K([1,0]),K([-270,0]),K([-1708,0])])
 
Copy content gp:E = ellinit([Polrev([0,0]),Polrev([0,0]),Polrev([1,0]),Polrev([-270,0]),Polrev([-1708,0])], K);
 
Copy content magma:E := EllipticCurve([K![0,0],K![0,0],K![1,0],K![-270,0],K![-1708,0]]);
 
Copy content oscar:E = elliptic_curve([K([0,0]),K([0,0]),K([1,0]),K([-270,0]),K([-1708,0])])
 

This is not a global minimal model: it is minimal at all primes except \((3,a)\). No global minimal model exists.

Copy content comment:Test whether it is a global minimal model
 
Copy content sage:E.is_global_minimal_model()
 

Mordell-Weil group structure

trivial

Invariants

Conductor: $\frak{N}$ = \((9)\) = \((3,a)^{4}\)
Copy content comment:Compute the conductor
 
Copy content sage:E.conductor()
 
Copy content gp:ellglobalred(E)[1]
 
Copy content magma:Conductor(E);
 
Copy content oscar:conductor(E)
 
Conductor norm: $N(\frak{N})$ = \( 81 \) = \(3^{4}\)
Copy content comment:Compute the norm of the conductor
 
Copy content sage:E.conductor().norm()
 
Copy content gp:idealnorm(K, ellglobalred(E)[1])
 
Copy content magma:Norm(Conductor(E));
 
Copy content oscar:norm(conductor(E))
 
Discriminant: $\Delta$ = $177147$
Discriminant ideal: $(\Delta)$ = \((177147)\) = \((3,a)^{22}\)
Copy content comment:Compute the discriminant
 
Copy content sage:E.discriminant()
 
Copy content gp:E.disc
 
Copy content magma:Discriminant(E);
 
Copy content oscar:discriminant(E)
 
Discriminant norm: $N(\Delta)$ = \( 31381059609 \) = \(3^{22}\)
Copy content comment:Compute the norm of the discriminant
 
Copy content sage:E.discriminant().norm()
 
Copy content gp:norm(E.disc)
 
Copy content magma:Norm(Discriminant(E));
 
Copy content oscar:norm(discriminant(E))
 
Minimal discriminant: $\frak{D}_{\mathrm{min}}$ = \((243)\) = \((3,a)^{10}\)
Minimal discriminant norm: $N(\frak{D}_{\mathrm{min}})$ = \( 59049 \) = \(3^{10}\)
j-invariant: $j$ = \( -12288000 \)
Copy content comment:Compute the j-invariant
 
Copy content sage:E.j_invariant()
 
Copy content gp:E.j
 
Copy content magma:jInvariant(E);
 
Copy content oscar:j_invariant(E)
 
Endomorphism ring: $\mathrm{End}(E)$ = \(\Z\)   
Geometric endomorphism ring: $\mathrm{End}(E_{\overline{\Q}})$ = \(\Z[(1+\sqrt{-27})/2]\)    (potential complex multiplication)
Copy content comment:Test for Complex Multiplication
 
Copy content sage:E.has_cm(), E.cm_discriminant()
 
Copy content magma:HasComplexMultiplication(E);
 
Sato-Tate group: $\mathrm{ST}(E)$ = $N(\mathrm{U}(1))$

BSD invariants

Analytic rank: $r_{\mathrm{an}}$= \( 0 \)
Copy content comment:Compute the Mordell-Weil rank
 
Copy content sage:E.rank()
 
Copy content magma:Rank(E);
 
Mordell-Weil rank: $r$ = \(0\)
Regulator: $\mathrm{Reg}(E/K)$ = \( 1 \)
Néron-Tate Regulator: $\mathrm{Reg}_{\mathrm{NT}}(E/K)$ = \( 1 \)
Global period: $\Omega(E/K)$ \( 5.4057521760417964272308686802584068242 \)
Tamagawa product: $\prod_{\frak{p}}c_{\frak{p}}$= \( 1 \)
Torsion order: $\#E(K)_{\mathrm{tor}}$= \(1\)
Special value: $L^{(r)}(E/K,1)/r!$ \( 0.35800468357210651254883728516992429443 \)
Analytic order of Ш: Ш${}_{\mathrm{an}}$= \( 1 \) (rounded)

BSD formula

$$\begin{aligned}0.358004684 \approx L(E/K,1) & \overset{?}{=} \frac{ \# ะจ(E/K) \cdot \Omega(E/K) \cdot \mathrm{Reg}_{\mathrm{NT}}(E/K) \cdot \prod_{\mathfrak{p}} c_{\mathfrak{p}} } { \#E(K)_{\mathrm{tor}}^2 \cdot \left|d_K\right|^{1/2} } \\ & \approx \frac{ 1 \cdot 5.405752 \cdot 1 \cdot 1 } { {1^2 \cdot 15.099669} } \\ & \approx 0.358004684 \end{aligned}$$

Local data at primes of bad reduction

Copy content comment:Compute the local reduction data at primes of bad reduction
 
Copy content sage:E.local_data()
 
Copy content magma:LocalInformation(E);
 

This elliptic curve is not semistable. There is only one prime $\frak{p}$ of bad reduction. Primes of good reduction for the curve but which divide the discriminant of the model above (if any) are included.

$\mathfrak{p}$ $N(\mathfrak{p})$ Tamagawa number Kodaira symbol Reduction type Root number \(\mathrm{ord}_{\mathfrak{p}}(\mathfrak{N}\)) \(\mathrm{ord}_{\mathfrak{p}}(\mathfrak{D}_{\mathrm{min}}\)) \(\mathrm{ord}_{\mathfrak{p}}(\mathrm{den}(j))\)
\((3,a)\) \(3\) \(1\) \(IV^{*}\) Additive \(-1\) \(4\) \(10\) \(0\)

Galois Representations

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

prime Image of Galois Representation
\(3\) 3Cs.1.1

For all other primes \(p\), the image is the normalizer of a split Cartan subgroup if \(\left(\frac{ -3 }{p}\right)=+1\) or the normalizer of a nonsplit Cartan subgroup if \(\left(\frac{ -3 }{p}\right)=-1\).

Isogenies and isogeny class

This curve has non-trivial cyclic isogenies of degree \(d\) for \(d=\) 3, 9 and 27.
Its isogeny class 81.1-b consists of curves linked by isogenies of degrees dividing 27.

Base change

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

Base field Curve
\(\Q\) 27.a1
\(\Q\) 155952.bm2