Properties

Label 4.4.9909.1-21.1-a2
Base field 4.4.9909.1
Conductor norm \( 21 \)
CM no
Base change no
Q-curve no
Torsion order \( 4 \)
Rank \( 1 \)

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Base field 4.4.9909.1

Generator \(a\), with minimal polynomial \( x^{4} - 6 x^{2} - 3 x + 3 \); class number \(1\).

Copy content comment:Define the base number field
 
Copy content sage:R.<x> = PolynomialRing(QQ); K.<a> = NumberField(R([3, -3, -6, 0, 1]))
 
Copy content gp:K = nfinit(Polrev([3, -3, -6, 0, 1]));
 
Copy content magma:R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![3, -3, -6, 0, 1]);
 

Weierstrass equation

\({y}^2+{x}{y}+\left(a^{2}-2\right){y}={x}^{3}+a{x}^{2}+\left(-13750a^{3}+16600a^{2}+62447a-34158\right){x}+1313070a^{3}-1585569a^{2}-5963840a+3262240\)
Copy content comment:Define the curve
 
Copy content sage:E = EllipticCurve([K([1,0,0,0]),K([0,1,0,0]),K([-2,0,1,0]),K([-34158,62447,16600,-13750]),K([3262240,-5963840,-1585569,1313070])])
 
Copy content gp:E = ellinit([Polrev([1,0,0,0]),Polrev([0,1,0,0]),Polrev([-2,0,1,0]),Polrev([-34158,62447,16600,-13750]),Polrev([3262240,-5963840,-1585569,1313070])], K);
 
Copy content magma:E := EllipticCurve([K![1,0,0,0],K![0,1,0,0],K![-2,0,1,0],K![-34158,62447,16600,-13750],K![3262240,-5963840,-1585569,1313070]]);
 

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

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

Mordell-Weil generators

$P$$\hat{h}(P)$Order
$\left(\frac{35588434}{1113025} a^{3} - \frac{41646111}{1113025} a^{2} - \frac{32178412}{222605} a + \frac{88379063}{1113025} : -\frac{20256966794}{1174241375} a^{3} + \frac{19955954476}{1174241375} a^{2} + \frac{17108767582}{234848275} a - \frac{45430592508}{1174241375} : 1\right)$$4.2563373253223029300708455110830687319$$\infty$
$\left(32 a^{3} - 38 a^{2} - 145 a + \frac{319}{4} : -16 a^{3} + \frac{37}{2} a^{2} + \frac{145}{2} a - \frac{311}{8} : 1\right)$$0$$2$
$\left(32 a^{3} - 39 a^{2} - 146 a + 80 : -16 a^{3} + 19 a^{2} + 73 a - 39 : 1\right)$$0$$2$

Invariants

Conductor: $\frak{N}$ = \((a-3)\) = \((-a^3+a^2+4a)\cdot(a^3-a^2-4a+1)\)
Copy content comment:Compute the conductor
 
Copy content sage:E.conductor()
 
Copy content gp:ellglobalred(E)[1]
 
Copy content magma:Conductor(E);
 
Conductor norm: $N(\frak{N})$ = \( 21 \) = \(3\cdot7\)
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: $\Delta$ = $-2487a^3+2531a^2+9684a-1314$
Discriminant ideal: $\frak{D}_{\mathrm{min}} = (\Delta)$ = \((-2487a^3+2531a^2+9684a-1314)\) = \((-a^3+a^2+4a)^{2}\cdot(a^3-a^2-4a+1)^{16}\)
Copy content comment:Compute the discriminant
 
Copy content sage:E.discriminant()
 
Copy content gp:E.disc
 
Copy content magma:Discriminant(E);
 
Discriminant norm: $N(\frak{D}_{\mathrm{min}}) = N(\Delta)$ = \( 299096375126409 \) = \(3^{2}\cdot7^{16}\)
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: $j$ = \( \frac{3075730896093395126238965002}{99698791708803} a^{3} - \frac{3714007662409537173380188813}{99698791708803} a^{2} - \frac{4656548508714567651606714255}{33232930569601} a + \frac{2547146210989604914629326570}{33232930569601} \)
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: $\mathrm{End}(E)$ = \(\Z\)   
Geometric endomorphism ring: $\mathrm{End}(E_{\overline{\Q}})$ = \(\Z\)    (no 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: $\mathrm{ST}(E)$ = $\mathrm{SU}(2)$

BSD invariants

Analytic rank: $r_{\mathrm{an}}$= \( 1 \)
Copy content comment:Compute the Mordell-Weil rank
 
Copy content sage:E.rank()
 
Copy content magma:Rank(E);
 
Mordell-Weil rank: $r$ = \(1\)
Regulator: $\mathrm{Reg}(E/K)$ \( 4.2563373253223029300708455110830687319 \)
Néron-Tate Regulator: $\mathrm{Reg}_{\mathrm{NT}}(E/K)$ \( 17.025349301289211720283382044332274928 \)
Global period: $\Omega(E/K)$ \( 87.105030326823751242452985106402193751 \)
Tamagawa product: $\prod_{\frak{p}}c_{\frak{p}}$= \( 4 \)  =  \(2\cdot2\)
Torsion order: $\#E(K)_{\mathrm{tor}}$= \(4\)
Special value: $L^{(r)}(E/K,1)/r!$ \( 3.72446898122785 \)
Analytic order of Ш: Ш${}_{\mathrm{an}}$= \( 1 \) (rounded)

BSD formula

$$\begin{aligned}3.724468981 \approx L'(E/K,1) & \overset{?}{=} \frac{ \# ะจ(E/K) \cdot \Omega(E/K) \cdot \mathrm{Reg}_{\mathrm{NT}}(E/K) \cdot \prod_{\mathfrak{p}} c_{\mathfrak{p}} } { \#E(K)_{\mathrm{tor}}^2 \cdot \left|d_K\right|^{1/2} } \\ & \approx \frac{ 1 \cdot 87.105030 \cdot 17.025349 \cdot 4 } { {4^2 \cdot 99.543960} } \\ & \approx 3.724468981 \end{aligned}$$

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 semistable. There are 2 primes $\frak{p}$ of bad reduction.

$\mathfrak{p}$ $N(\mathfrak{p})$ Tamagawa number Kodaira symbol Reduction type Root number \(\mathrm{ord}_{\mathfrak{p}}(\mathfrak{N}\)) \(\mathrm{ord}_{\mathfrak{p}}(\mathfrak{D}_{\mathrm{min}}\)) \(\mathrm{ord}_{\mathfrak{p}}(\mathrm{den}(j))\)
\((-a^3+a^2+4a)\) \(3\) \(2\) \(I_{2}\) Split multiplicative \(-1\) \(1\) \(2\) \(2\)
\((a^3-a^2-4a+1)\) \(7\) \(2\) \(I_{16}\) Non-split multiplicative \(1\) \(1\) \(16\) \(16\)

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 and 4.
Its isogeny class 21.1-a consists of curves linked by isogenies of degrees dividing 8.

Base change

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

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