Properties

Label 2.0.4.1-50625.3-CMa1
Base field \(\Q(\sqrt{-1}) \)
Conductor norm \( 50625 \)
CM yes (\(-4\))
Base change no
Q-curve yes
Torsion order \( 2 \)
Rank \( 2 \)

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Base field \(\Q(\sqrt{-1}) \)

Generator \(i\), with minimal polynomial \( x^{2} + 1 \); class number \(1\).

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

Weierstrass equation

\({y}^2+\left(i+1\right){x}{y}+i{y}={x}^{3}+i{x}^{2}+\left(-8i-4\right){x}-2i+4\)
Copy content comment:Define the curve
 
Copy content sage:E = EllipticCurve([K([1,1]),K([0,1]),K([0,1]),K([-4,-8]),K([4,-2])])
 
Copy content gp:E = ellinit([Polrev([1,1]),Polrev([0,1]),Polrev([0,1]),Polrev([-4,-8]),Polrev([4,-2])], K);
 
Copy content magma:E := EllipticCurve([K![1,1],K![0,1],K![0,1],K![-4,-8],K![4,-2]]);
 

This is a global minimal model.

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

Mordell-Weil group structure

\(\Z \oplus \Z \oplus \Z/{2}\Z\)

Mordell-Weil generators

$P$$\hat{h}(P)$Order
$\left(i - 3 : 5 i + 8 : 1\right)$$0.28604436597441380647433200237382647413$$\infty$
$\left(-2 i - 3 : 5 i - 1 : 1\right)$$0.57208873194882761294866400474765294826$$\infty$
$\left(-\frac{1}{2} i : -\frac{1}{4} i - \frac{1}{4} : 1\right)$$0$$2$

Invariants

Conductor: $\frak{N}$ = \((225)\) = \((-i-2)^{2}\cdot(2i+1)^{2}\cdot(3)^{2}\)
Copy content comment:Compute the conductor
 
Copy content sage:E.conductor()
 
Copy content gp:ellglobalred(E)[1]
 
Copy content magma:Conductor(E);
 
Conductor norm: $N(\frak{N})$ = \( 50625 \) = \(5^{2}\cdot5^{2}\cdot9^{2}\)
Copy content comment:Compute the norm of the conductor
 
Copy content sage:E.conductor().norm()
 
Copy content gp:idealnorm(ellglobalred(E)[1])
 
Copy content magma:Norm(Conductor(E));
 
Discriminant: $\Delta$ = $-6750i-37125$
Discriminant ideal: $\frak{D}_{\mathrm{min}} = (\Delta)$ = \((-6750i-37125)\) = \((-i-2)^{3}\cdot(2i+1)^{6}\cdot(3)^{3}\)
Copy content comment:Compute the discriminant
 
Copy content sage:E.discriminant()
 
Copy content gp:E.disc
 
Copy content magma:Discriminant(E);
 
Discriminant norm: $N(\frak{D}_{\mathrm{min}}) = N(\Delta)$ = \( 1423828125 \) = \(5^{3}\cdot5^{6}\cdot9^{3}\)
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));
 
j-invariant: $j$ = \( 1728 \)
Copy content comment:Compute the j-invariant
 
Copy content sage:E.j_invariant()
 
Copy content gp:E.j
 
Copy content magma:jInvariant(E);
 
Endomorphism ring: $\mathrm{End}(E)$ = \(\Z[\sqrt{-1}]\)    (complex multiplication)
Geometric endomorphism ring: $\mathrm{End}(E_{\overline{\Q}})$ = \(\Z[\sqrt{-1}]\)   
Copy content comment:Test for Complex Multiplication
 
Copy content sage:E.has_cm(), E.cm_discriminant()
 
Copy content magma:HasComplexMultiplication(E);
 
Sato-Tate group: $\mathrm{ST}(E)$ = $\mathrm{U}(1)$

BSD invariants

Analytic rank: $r_{\mathrm{an}}$= \( 2 \)
Copy content comment:Compute the Mordell-Weil rank
 
Copy content sage:E.rank()
 
Copy content magma:Rank(E);
 
Mordell-Weil rank: $r$ = \(2\)
Regulator: $\mathrm{Reg}(E/K)$ \( 0.081821379305704382989848639084196312533 \)
Néron-Tate Regulator: $\mathrm{Reg}_{\mathrm{NT}}(E/K)$ \( 0.3272855172228175319593945563367852501320 \)
Global period: $\Omega(E/K)$ \( 4.7484984568444214166053248235430101992 \)
Tamagawa product: $\prod_{\frak{p}}c_{\frak{p}}$= \( 16 \)  =  \(2\cdot2^{2}\cdot2\)
Torsion order: $\#E(K)_{\mathrm{tor}}$= \(2\)
Special value: $L^{(r)}(E/K,1)/r!$ \( 3.1082295469601547171332274425357836600 \)
Analytic order of Ш: Ш${}_{\mathrm{an}}$= \( 1 \) (rounded)

BSD formula

$$\begin{aligned}3.108229547 \approx L^{(2)}(E/K,1)/2! & \overset{?}{=} \frac{ \# ะจ(E/K) \cdot \Omega(E/K) \cdot \mathrm{Reg}_{\mathrm{NT}}(E/K) \cdot \prod_{\mathfrak{p}} c_{\mathfrak{p}} } { \#E(K)_{\mathrm{tor}}^2 \cdot \left|d_K\right|^{1/2} } \\ & \approx \frac{ 1 \cdot 4.748498 \cdot 0.327286 \cdot 16 } { {2^2 \cdot 2.000000} } \\ & \approx 3.108229547 \end{aligned}$$

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 are 3 primes $\frak{p}$ of bad reduction.

$\mathfrak{p}$ $N(\mathfrak{p})$ Tamagawa number Kodaira symbol Reduction type Root number \(\mathrm{ord}_{\mathfrak{p}}(\mathfrak{N}\)) \(\mathrm{ord}_{\mathfrak{p}}(\mathfrak{D}_{\mathrm{min}}\)) \(\mathrm{ord}_{\mathfrak{p}}(\mathrm{den}(j))\)
\((-i-2)\) \(5\) \(2\) \(III\) Additive \(-1\) \(2\) \(3\) \(0\)
\((2i+1)\) \(5\) \(4\) \(I_0^{*}\) Additive \(1\) \(2\) \(6\) \(0\)
\((3)\) \(9\) \(2\) \(III\) Additive \(1\) \(2\) \(3\) \(0\)

Galois Representations

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

The image is a Borel subgroup if \(p=2\), a split Cartan subgroup if \(\left(\frac{ -1 }{p}\right)=+1\) or a nonsplit Cartan subgroup if \(\left(\frac{ -1 }{p}\right)=-1\).

Isogenies and isogeny class

This curve has no rational isogenies other than endomorphisms. Its isogeny class 50625.3-CMa consists of this curve only.

Base change

This elliptic curve is a \(\Q\)-curve.

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