Base field \(\Q(\sqrt{7}) \)
Generator \(a\), with minimal polynomial \( x^{2} - 7 \); class number \(1\).
Weierstrass equation
This is a global minimal model.
Mordell-Weil group structure
\(\Z \oplus \Z/{2}\Z\)
Mordell-Weil generators
$P$ | $\hat{h}(P)$ | Order |
---|---|---|
$\left(64 a + 171 : -523 a - 1381 : 1\right)$ | $0.64528977739308943704780835994917297593$ | $\infty$ |
$\left(\frac{101}{2} a + 135 : -\frac{373}{4} a - \frac{979}{4} : 1\right)$ | $0$ | $2$ |
Invariants
Conductor: | $\frak{N}$ | = | \((18a+54)\) | = | \((a+3)^{3}\cdot(-a+2)^{2}\cdot(-a-2)^{2}\) |
sage: E.conductor()
gp: ellglobalred(E)[1]
magma: Conductor(E);
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Conductor norm: | $N(\frak{N})$ | = | \( 648 \) | = | \(2^{3}\cdot3^{2}\cdot3^{2}\) |
sage: E.conductor().norm()
gp: idealnorm(ellglobalred(E)[1])
magma: Norm(Conductor(E));
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Discriminant: | $\Delta$ | = | $209952$ | ||
Discriminant ideal: | $\frak{D}_{\mathrm{min}} = (\Delta)$ | = | \((209952)\) | = | \((a+3)^{10}\cdot(-a+2)^{8}\cdot(-a-2)^{8}\) |
sage: E.discriminant()
gp: E.disc
magma: Discriminant(E);
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Discriminant norm: | $N(\frak{D}_{\mathrm{min}}) = N(\Delta)$ | = | \( 44079842304 \) | = | \(2^{10}\cdot3^{8}\cdot3^{8}\) |
sage: E.discriminant().norm()
gp: norm(E.disc)
magma: Norm(Discriminant(E));
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j-invariant: | $j$ | = | \( \frac{3065617154}{9} \) | ||
sage: E.j_invariant()
gp: E.j
magma: jInvariant(E);
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Endomorphism ring: | $\mathrm{End}(E)$ | = | \(\Z\) | ||
Geometric endomorphism ring: | $\mathrm{End}(E_{\overline{\Q}})$ | = | \(\Z\) (no potential complex multiplication) | ||
sage: E.has_cm(), E.cm_discriminant()
magma: HasComplexMultiplication(E);
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Sato-Tate group: | $\mathrm{ST}(E)$ | = | $\mathrm{SU}(2)$ |
BSD invariants
Analytic rank: | $r_{\mathrm{an}}$ | = | \( 1 \) |
sage: E.rank()
magma: Rank(E);
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Mordell-Weil rank: | $r$ | = | \(1\) |
Regulator: | $\mathrm{Reg}(E/K)$ | ≈ | \( 0.64528977739308943704780835994917297593 \) |
Néron-Tate Regulator: | $\mathrm{Reg}_{\mathrm{NT}}(E/K)$ | ≈ | \( 1.29057955478617887409561671989834595186 \) |
Global period: | $\Omega(E/K)$ | ≈ | \( 7.5780113566687825347161968372579115861 \) |
Tamagawa product: | $\prod_{\frak{p}}c_{\frak{p}}$ | = | \( 8 \) = \(2\cdot2\cdot2\) |
Torsion order: | $\#E(K)_{\mathrm{tor}}$ | = | \(2\) |
Special value: | $L^{(r)}(E/K,1)/r!$ | ≈ | \( 3.6965025707268544718535305611532899795 \) |
Analytic order of Ш: | Ш${}_{\mathrm{an}}$ | = | \( 1 \) (rounded) |
BSD formula
$\displaystyle 3.696502571 \approx L'(E/K,1) \overset{?}{=} \frac{ \# Ш(E/K) \cdot \Omega(E/K) \cdot \mathrm{Reg}_{\mathrm{NT}}(E/K) \cdot \prod_{\mathfrak{p}} c_{\mathfrak{p}} } { \#E(K)_{\mathrm{tor}}^2 \cdot \left|d_K\right|^{1/2} } \approx \frac{ 1 \cdot 7.578011 \cdot 1.290580 \cdot 8 } { {2^2 \cdot 5.291503} } \approx 3.696502571$
Local data at primes of bad reduction
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 | \(\mathrm{ord}_{\mathfrak{p}}(\mathfrak{N}\)) | \(\mathrm{ord}_{\mathfrak{p}}(\mathfrak{D}_{\mathrm{min}}\)) | \(\mathrm{ord}_{\mathfrak{p}}(\mathrm{den}(j))\) |
---|---|---|---|---|---|---|---|---|
\((a+3)\) | \(2\) | \(2\) | \(III^{*}\) | Additive | \(-1\) | \(3\) | \(10\) | \(0\) |
\((-a+2)\) | \(3\) | \(2\) | \(I_{2}^{*}\) | Additive | \(-1\) | \(2\) | \(8\) | \(2\) |
\((-a-2)\) | \(3\) | \(2\) | \(I_{2}^{*}\) | Additive | \(-1\) | \(2\) | \(8\) | \(2\) |
Galois Representations
The mod \( p \) Galois Representation has maximal image for all primes \( p < 1000 \) except those listed.
prime | Image of Galois Representation |
---|---|
\(2\) | 2B |
Isogenies and isogeny class
This curve has non-trivial cyclic isogenies of degree \(d\) for \(d=\)
2, 4 and 8.
Its isogeny class
648.1-m
consists of curves linked by isogenies of
degrees dividing 8.
Base change
This elliptic curve is a \(\Q\)-curve. It is the base change of the following 2 elliptic curves:
Base field | Curve |
---|---|
\(\Q\) | 72.a1 |
\(\Q\) | 7056.q1 |