This is a model for the Fermat cubic curve $X^3+Y^3=Z^3$ and for the modular curve $X_0(27)$.
Minimal Weierstrass equation
\(y^2+y=x^3-7\) 
Mordell-Weil group structure
\(\Z/{3}\Z\)
Torsion generators
\( \left(3, 4\right) \)
Integral points
\( \left(3, 4\right) \), \( \left(3, -5\right) \)
Invariants
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sage: E.conductor().factor()
gp: ellglobalred(E)[1]
magma: Conductor(E);
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| Conductor: | \( 27 \) | = | \(3^{3}\) |
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sage: E.discriminant().factor()
gp: E.disc
magma: Discriminant(E);
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| Discriminant: | \(-19683 \) | = | \(-1 \cdot 3^{9} \) |
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sage: E.j_invariant().factor()
gp: E.j
magma: jInvariant(E);
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| j-invariant: | \( 0 \) | = | \(0\) |
| Endomorphism ring: | \(\Z\) | ||
| Geometric endomorphism ring: | \(\Z[(1+\sqrt{-3})/2]\) | (potential complex multiplication) | |
| Sato-Tate group: | $N(\mathrm{U}(1))$ | ||
| Faltings height: | \(-0.49715821192695564644343526816\dots\) | ||
| Stable Faltings height: | \(-1.3211174284280379149898691959\dots\) | ||
BSD invariants
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sage: E.rank()
magma: Rank(E);
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| Analytic rank: | \(0\) | ||
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sage: E.regulator()
magma: Regulator(E);
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| Regulator: | \(1\) | ||
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sage: E.period_lattice().omega()
gp: E.omega[1]
magma: RealPeriod(E);
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| Real period: | \(1.7666387502854499573136894996\dots\) | ||
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sage: E.tamagawa_numbers()
gp: gr=ellglobalred(E); [[gr[4][i,1],gr[5][i][4]] | i<-[1..#gr[4][,1]]]
magma: TamagawaNumbers(E);
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| Tamagawa product: | \( 3 \) = \( 3 \) | ||
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sage: E.torsion_order()
gp: elltors(E)[1]
magma: Order(TorsionSubgroup(E));
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| Torsion order: | \(3\) | ||
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sage: E.sha().an_numerical()
magma: MordellWeilShaInformation(E);
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| Analytic order of Ш: | \(1\) (exact) | ||
Modular invariants
For more coefficients, see the Downloads section to the right.
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sage: E.modular_degree()
magma: ModularDegree(E);
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| Modular degree: | 1 | ||
| \( \Gamma_0(N) \)-optimal: | yes | ||
| Manin constant: | 1 | ||
Special L-value
\( L(E,1) \) ≈ \( 0.58887958342848331910456316654932546833 \)
Local data
This elliptic curve is not semistable. There is only one prime of bad reduction:
| prime | Tamagawa number | Kodaira symbol | Reduction type | Root number | ord(\(N\)) | ord(\(\Delta\)) | ord\((j)_{-}\) |
|---|---|---|---|---|---|---|---|
| \(3\) | \(3\) | \(IV^{*}\) | Additive | -1 | 3 | 9 | 0 |
Galois representations
The mod \( p \) Galois representation has maximal image for all primes \( p < 1000 \) except those listed.
| prime | Image of Galois representation |
|---|---|
| \(3\) | Cs.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 \(\left(\frac{ -3 }{p}\right)=-1\).
$p$-adic data
$p$-adic regulators
All \(p\)-adic regulators are identically \(1\) since the rank is \(0\).
Iwasawa invariants
| $p$ | 2 | 3 |
|---|---|---|
| Reduction type | ss | add |
| $\lambda$-invariant(s) | 0,5 | - |
| $\mu$-invariant(s) | 0,0 | - |
All Iwasawa $\lambda$ and $\mu$-invariants for primes $p\ge 5$ of good reduction are zero.
An entry - indicates that the invariants are not computed because the reduction is additive.
Isogenies
This curve has non-trivial cyclic isogenies of degree \(d\) for \(d=\)
3 and 9.
Its isogeny class 27a
consists of 4 curves linked by isogenies of
degrees dividing 27.
Growth of torsion in number fields
The number fields $K$ of degree less than 24 such that $E(K)_{\rm tors}$ is strictly larger than $E(\Q)_{\rm tors}$ $\cong \Z/{3}\Z$ are as follows:
| $[K:\Q]$ | $K$ | $E(K)_{\rm tors}$ | Base change curve |
|---|---|---|---|
| $2$ | \(\Q(\sqrt{-3}) \) | \(\Z/3\Z \times \Z/3\Z\) | 2.0.3.1-81.1-CMa1 |
| $3$ | 3.1.108.1 | \(\Z/6\Z\) | Not in database |
| $6$ | 6.0.34992.1 | \(\Z/6\Z \times \Z/6\Z\) | Not in database |
| $6$ | \(\Q(\zeta_{9})\) | \(\Z/3\Z \times \Z/9\Z\) | Not in database |
| $9$ | 9.3.1162261467.1 | \(\Z/9\Z\) | Not in database |
| $12$ | 12.2.15045919506432.1 | \(\Z/12\Z\) | Not in database |
| $12$ | 12.0.241162079949.1 | \(\Z/3\Z \times \Z/21\Z\) | Not in database |
| $18$ | 18.0.4052555153018976267.1 | \(\Z/9\Z \times \Z/9\Z\) | Not in database |
| $18$ | 18.0.2529990231179046912.1 | \(\Z/6\Z \times \Z/18\Z\) | Not in database |
We only show fields where the torsion growth is primitive.