Properties

Label 42042.db1
Conductor 42042
Discriminant 444791982921302016
j-invariant \( \frac{28826282175168869972161}{9077387406557184} \)
CM no
Rank 1
Torsion Structure \(\Z/{7}\Z\)

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Minimal Weierstrass equation

magma: E := EllipticCurve([1, 0, 0, -2337511, 1374987977]); // or
magma: E := EllipticCurve("42042dk2");
sage: E = EllipticCurve([1, 0, 0, -2337511, 1374987977]) # or
sage: E = EllipticCurve("42042dk2")
gp: E = ellinit([1, 0, 0, -2337511, 1374987977]) \\ or
gp: E = ellinit("42042dk2")

\( y^2 + x y = x^{3} - 2337511 x + 1374987977 \)

Mordell-Weil group structure

\(\Z\times \Z/{7}\Z\)

Infinite order Mordell-Weil generator and height

magma: Generators(E);
sage: E.gens()

\(P\) =  \( \left(-1738, 14597\right) \)
\(\hat{h}(P)\) ≈  2.50042406946

Torsion generators

magma: TorsionSubgroup(E);
sage: E.torsion_subgroup().gens()
gp: elltors(E)

\( \left(902, 341\right) \)

Integral points

magma: IntegralPoints(E);
sage: E.integral_points()

\( \left(-1738, 14597\right) \), \( \left(-286, 45089\right) \), \( \left(866, 161\right) \), \( \left(902, 341\right) \), \( \left(1034, 7469\right) \), \( \left(2486, 103301\right) \)

Note: only one of each pair $\pm P$ is listed.

Invariants

magma: Conductor(E);
sage: E.conductor().factor()
gp: ellglobalred(E)[1]
Conductor: \( 42042 \)  =  \(2 \cdot 3 \cdot 7^{2} \cdot 11 \cdot 13\)
magma: Discriminant(E);
sage: E.discriminant().factor()
gp: E.disc
Discriminant: \(444791982921302016 \)  =  \(2^{14} \cdot 3^{7} \cdot 7^{2} \cdot 11^{7} \cdot 13 \)
magma: jInvariant(E);
sage: E.j_invariant().factor()
gp: E.j
j-invariant: \( \frac{28826282175168869972161}{9077387406557184} \)  =  \(2^{-14} \cdot 3^{-7} \cdot 7 \cdot 11^{-7} \cdot 13^{-1} \cdot 19^{3} \cdot 843613^{3}\)
Endomorphism ring: \(\Z\)   (no Complex Multiplication)
Sato-Tate Group: $\mathrm{SU}(2)$

BSD invariants

magma: Rank(E);
sage: E.rank()
Rank: \(1\)
magma: Regulator(E);
sage: E.regulator()
Regulator: \(2.50042406946\)
magma: RealPeriod(E);
sage: E.period_lattice().omega()
gp: E.omega[1]
Real period: \(0.290926865768\)
magma: TamagawaNumbers(E);
sage: E.tamagawa_numbers()
gp: gr=ellglobalred(E); [[gr[4][i,1],gr[5][i][4]] | i<-[1..#gr[4][,1]]]
Tamagawa product: \( 686 \)  = \( ( 2 \cdot 7 )\cdot7\cdot1\cdot7\cdot1 \)
magma: Order(TorsionSubgroup(E));
sage: E.torsion_order()
gp: elltors(E)[1]
Torsion order: \(7\)
magma: MordellWeilShaInformation(E);
sage: E.sha().an_numerical()
Analytic order of Ш: \(1\) (exact)

Modular invariants

Modular form 42042.2.a.db

magma: ModularForm(E);
sage: E.q_eigenform(20)
gp: xy = elltaniyama(E);
gp: x*deriv(xy[1])/(2*xy[2]+E.a1*xy[1]+E.a3)

\( q + q^{2} + q^{3} + q^{4} - q^{5} + q^{6} + q^{8} + q^{9} - q^{10} + q^{11} + q^{12} - q^{13} - q^{15} + q^{16} - 3q^{17} + q^{18} - q^{19} + O(q^{20}) \)

For more coefficients, see the Downloads section to the right.

magma: ModularDegree(E);
sage: E.modular_degree()
Modular degree: 1119552
\( \Gamma_0(N) \)-optimal: no
Manin constant: 1

Special L-value

magma: Lr1 where r,Lr1 := AnalyticRank(E: Precision:=12);
sage: r = E.rank();
sage: E.lseries().dokchitser().derivative(1,r)/r.factorial()
gp: ar = ellanalyticrank(E);
gp: ar[2]/factorial(ar[1])

\( L'(E,1) \) ≈ \( 10.1841675267 \)

Local data

magma: [LocalInformation(E,p) : p in BadPrimes(E)];
sage: E.local_data()
gp: ellglobalred(E)[5]
prime Tamagawa number Kodaira symbol Reduction type Root number ord(\(N\)) ord(\(\Delta\)) ord\((j)_{-}\)
\(2\) \(14\) \( I_{14} \) Split multiplicative -1 1 14 14
\(3\) \(7\) \( I_{7} \) Split multiplicative -1 1 7 7
\(7\) \(1\) \( II \) Additive -1 2 2 0
\(11\) \(7\) \( I_{7} \) Split multiplicative -1 1 7 7
\(13\) \(1\) \( I_{1} \) Non-split multiplicative 1 1 1 1

Galois representations

The 2-adic representation attached to this elliptic curve is surjective.

magma: [GaloisRepresentation(E,p): p in PrimesUpTo(20)];
sage: rho = E.galois_representation();
sage: [rho.image_type(p) for p in rho.non_surjective()]

The mod \( p \) Galois representation has maximal image \(\GL(2,\F_p)\) for all primes \( p \) except those listed.

prime Image of Galois representation
\(7\) B.1.1

$p$-adic data

$p$-adic regulators

sage: [E.padic_regulator(p) for p in primes(3,20) if E.conductor().valuation(p)<2]

\(p\)-adic regulators are not yet computed for curves that are not \(\Gamma_0\)-optimal.

Iwasawa invariants

$p$ 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47
Reduction type split split ordinary add split nonsplit ordinary ordinary ordinary ordinary ordinary ordinary ss ordinary ordinary
$\lambda$-invariant(s) 3 2 1 - 2 3 1 1 1 1 1 1 1,1 1 1
$\mu$-invariant(s) 0 0 0 - 0 0 0 0 0 0 0 0 0,0 0 0

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 \(d=\) 7.
Its isogeny class 42042.db consists of 2 curves linked by isogenies of degree 7.

Growth of torsion in number fields

The number fields $K$ of degree up to 7 such that $E(K)_{\rm tors}$ is strictly larger than $E(\Q)_{\rm tors}$ $\cong \Z/{7}\Z$ are as follows:

$[K:\Q]$ $K$ $E(K)_{\rm tors}$ Base-change curve
3 3.3.21021.1 \(\Z/14\Z\) Not in database
6 6.6.189567567189.1 \(\Z/2\Z \times \Z/14\Z\) Not in database

We only show fields where the torsion growth is primitive. For each field $K$ we either show its label, or a defining polynomial when $K$ is not in the database.