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Properties

Label 19.a2
Conductor $19$
Discriminant $-6859$
j-invariant \( -\frac{89915392}{6859} \)
CM no
Rank $0$
Torsion structure \(\Z/{3}\Z\)

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Show commands: Magma / Oscar / PariGP / SageMath

This is a model for the modular curve $X_0(19)$.

Minimal Weierstrass equation

Minimal Weierstrass equation

Simplified equation

\(y^2+y=x^3+x^2-9x-15\) Copy content Toggle raw display (homogenize, simplify)
\(y^2z+yz^2=x^3+x^2z-9xz^2-15z^3\) Copy content Toggle raw display (dehomogenize, simplify)
\(y^2=x^3-12096x-544752\) Copy content Toggle raw display (homogenize, minimize)

comment: Define the curve
 
sage: E = EllipticCurve([0, 1, 1, -9, -15])
 
gp: E = ellinit([0, 1, 1, -9, -15])
 
magma: E := EllipticCurve([0, 1, 1, -9, -15]);
 
oscar: E = elliptic_curve([0, 1, 1, -9, -15])
 
sage: E.short_weierstrass_model()
 
magma: WeierstrassModel(E);
 
oscar: short_weierstrass_model(E)
 

Mordell-Weil group structure

\(\Z/{3}\Z\)

magma: MordellWeilGroup(E);
 

Mordell-Weil generators

$P$$\hat{h}(P)$Order
$(5, 9)$$0$$3$

Integral points

\( \left(5, 9\right) \), \( \left(5, -10\right) \) Copy content Toggle raw display

comment: Integral points
 
sage: E.integral_points()
 
magma: IntegralPoints(E);
 

Invariants

Conductor: $N$  =  \( 19 \) = $19$
comment: Conductor
 
sage: E.conductor().factor()
 
gp: ellglobalred(E)[1]
 
magma: Conductor(E);
 
oscar: conductor(E)
 
Discriminant: $\Delta$  =  $-6859$ = $-1 \cdot 19^{3} $
comment: Discriminant
 
sage: E.discriminant().factor()
 
gp: E.disc
 
magma: Discriminant(E);
 
oscar: discriminant(E)
 
j-invariant: $j$  =  \( -\frac{89915392}{6859} \) = $-1 \cdot 2^{18} \cdot 7^{3} \cdot 19^{-3}$
comment: j-invariant
 
sage: E.j_invariant().factor()
 
gp: E.j
 
magma: jInvariant(E);
 
oscar: j_invariant(E)
 
Endomorphism ring: $\mathrm{End}(E)$ = $\Z$
Geometric endomorphism ring: $\mathrm{End}(E_{\overline{\Q}})$  =  \(\Z\)    (no potential complex multiplication)
sage: E.has_cm()
 
magma: HasComplexMultiplication(E);
 
Sato-Tate group: $\mathrm{ST}(E)$ = $\mathrm{SU}(2)$
Faltings height: $h_{\mathrm{Faltings}}$ ≈ $-0.51586698734273704217752773488$
gp: ellheight(E)
 
magma: FaltingsHeight(E);
 
oscar: faltings_height(E)
 
Stable Faltings height: $h_{\mathrm{stable}}$ ≈ $-0.51586698734273704217752773488$
magma: StableFaltingsHeight(E);
 
oscar: stable_faltings_height(E)
 
$abc$ quality: $Q$ ≈ $1.0331037033479094$
Szpiro ratio: $\sigma_{m}$ ≈ $6.262043087240102$

BSD invariants

Analytic rank: $r_{\mathrm{an}}$ = $ 0$
sage: E.analytic_rank()
 
gp: ellanalyticrank(E)
 
magma: AnalyticRank(E);
 
Mordell-Weil rank: $r$ = $ 0$
comment: Rank
 
sage: E.rank()
 
gp: [lower,upper] = ellrank(E)
 
magma: Rank(E);
 
Regulator: $\mathrm{Reg}(E/\Q)$ = $1$
comment: Regulator
 
sage: E.regulator()
 
G = E.gen \\ if available
 
matdet(ellheightmatrix(E,G))
 
magma: Regulator(E);
 
Real period: $\Omega$ ≈ $1.3597597334883108107365175612$
comment: Real Period
 
sage: E.period_lattice().omega()
 
gp: if(E.disc>0,2,1)*E.omega[1]
 
magma: (Discriminant(E) gt 0 select 2 else 1) * RealPeriod(E);
 
Tamagawa product: $\prod_{p}c_p$ = $ 3 $  = $ 3 $
comment: Tamagawa numbers
 
sage: E.tamagawa_numbers()
 
gp: gr=ellglobalred(E); [[gr[4][i,1],gr[5][i][4]] | i<-[1..#gr[4][,1]]]
 
magma: TamagawaNumbers(E);
 
oscar: tamagawa_numbers(E)
 
Torsion order: $\#E(\Q)_{\mathrm{tor}}$ = $3$
comment: Torsion order
 
sage: E.torsion_order()
 
gp: elltors(E)[1]
 
magma: Order(TorsionSubgroup(E));
 
oscar: prod(torsion_structure(E)[1])
 
Special value: $ L(E,1)$ ≈ $0.45325324449610360357883918707 $
comment: Special L-value
 
r = E.rank();
 
E.lseries().dokchitser().derivative(1,r)/r.factorial()
 
gp: [r,L1r] = ellanalyticrank(E); L1r/r!
 
magma: Lr1 where r,Lr1 := AnalyticRank(E: Precision:=12);
 
Analytic order of Ш: Ш${}_{\mathrm{an}}$  =  $1$    (exact)
comment: Order of Sha
 
sage: E.sha().an_numerical()
 
magma: MordellWeilShaInformation(E);
 

BSD formula

$\displaystyle 0.453253244 \approx L(E,1) = \frac{\# Ш(E/\Q)\cdot \Omega_E \cdot \mathrm{Reg}(E/\Q) \cdot \prod_p c_p}{\#E(\Q)_{\rm tor}^2} \approx \frac{1 \cdot 1.359760 \cdot 1.000000 \cdot 3}{3^2} \approx 0.453253244$

# self-contained SageMath code snippet for the BSD formula (checks rank, computes analytic sha)
 
E = EllipticCurve(%s); r = E.rank(); ar = E.analytic_rank(); assert r == ar;
 
Lr1 = E.lseries().dokchitser().derivative(1,r)/r.factorial(); sha = E.sha().an_numerical();
 
omega = E.period_lattice().omega(); reg = E.regulator(); tam = E.tamagawa_product(); tor = E.torsion_order();
 
assert r == ar; print("analytic sha: " + str(RR(Lr1) * tor^2 / (omega * reg * tam)))
 
/* self-contained Magma code snippet for the BSD formula (checks rank, computes analytic sha) */
 
E := EllipticCurve(%s); r := Rank(E); ar,Lr1 := AnalyticRank(E: Precision := 12); assert r eq ar;
 
sha := MordellWeilShaInformation(E); omega := RealPeriod(E) * (Discriminant(E) gt 0 select 2 else 1);
 
reg := Regulator(E); tam := &*TamagawaNumbers(E); tor := #TorsionSubgroup(E);
 
assert r eq ar; print "analytic sha:", Lr1 * tor^2 / (omega * reg * tam);
 

Modular invariants

Modular form   19.2.a.a

\( q - 2 q^{3} - 2 q^{4} + 3 q^{5} - q^{7} + q^{9} + 3 q^{11} + 4 q^{12} - 4 q^{13} - 6 q^{15} + 4 q^{16} - 3 q^{17} + q^{19} + O(q^{20}) \) Copy content Toggle raw display

comment: q-expansion of modular form
 
sage: E.q_eigenform(20)
 
\\ actual modular form, use for small N
 
[mf,F] = mffromell(E)
 
Ser(mfcoefs(mf,20),q)
 
\\ or just the series
 
Ser(ellan(E,20),q)*q
 
magma: ModularForm(E);
 

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

Modular degree: 1
comment: Modular degree
 
sage: E.modular_degree()
 
gp: ellmoddegree(E)
 
magma: ModularDegree(E);
 
$ \Gamma_0(N) $-optimal: yes
Manin constant: 1
comment: Manin constant
 
magma: ManinConstant(E);
 

Local data at primes of bad reduction

This elliptic curve is semistable. There is only one prime $p$ of bad reduction:

$p$ Tamagawa number Kodaira symbol Reduction type Root number $\mathrm{ord}_p(N)$ $\mathrm{ord}_p(\Delta)$ $\mathrm{ord}_p(\mathrm{den}(j))$
$19$ $3$ $I_{3}$ split multiplicative -1 1 3 3

comment: Local data
 
sage: E.local_data()
 
gp: ellglobalred(E)[5]
 
magma: [LocalInformation(E,p) : p in BadPrimes(E)];
 
oscar: [(p,tamagawa_number(E,p), kodaira_symbol(E,p), reduction_type(E,p)) for p in bad_primes(E)]
 

Galois representations

The $\ell$-adic Galois representation has maximal image for all primes $\ell$ except those listed in the table below.

prime $\ell$ mod-$\ell$ image $\ell$-adic image
$3$ 3Cs.1.1 9.72.0.3

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

gens = [[43, 30, 840, 85], [892, 27, 15, 676], [935, 790, 714, 553], [973, 54, 972, 55], [1, 27, 27, 730], [1, 54, 0, 1], [19, 54, 792, 469], [1, 0, 54, 1]]
 
GL(2,Integers(1026)).subgroup(gens)
 
Gens := [[43, 30, 840, 85], [892, 27, 15, 676], [935, 790, 714, 553], [973, 54, 972, 55], [1, 27, 27, 730], [1, 54, 0, 1], [19, 54, 792, 469], [1, 0, 54, 1]];
 
sub<GL(2,Integers(1026))|Gens>;
 

The image $H:=\rho_E(\Gal(\overline{\Q}/\Q))$ of the adelic Galois representation has level \( 1026 = 2 \cdot 3^{3} \cdot 19 \), index $1296$, genus $43$, and generators

$\left(\begin{array}{rr} 43 & 30 \\ 840 & 85 \end{array}\right),\left(\begin{array}{rr} 892 & 27 \\ 15 & 676 \end{array}\right),\left(\begin{array}{rr} 935 & 790 \\ 714 & 553 \end{array}\right),\left(\begin{array}{rr} 973 & 54 \\ 972 & 55 \end{array}\right),\left(\begin{array}{rr} 1 & 27 \\ 27 & 730 \end{array}\right),\left(\begin{array}{rr} 1 & 54 \\ 0 & 1 \end{array}\right),\left(\begin{array}{rr} 19 & 54 \\ 792 & 469 \end{array}\right),\left(\begin{array}{rr} 1 & 0 \\ 54 & 1 \end{array}\right)$.

Input positive integer $m$ to see the generators of the reduction of $H$ to $\mathrm{GL}_2(\Z/m\Z)$:

The torsion field $K:=\Q(E[1026])$ is a degree-$179508960$ Galois extension of $\Q$ with $\Gal(K/\Q)$ isomorphic to the projection of $H$ to $\GL_2(\Z/1026\Z)$.

The table below list all primes $\ell$ for which the Serre invariants associated to the mod-$\ell$ Galois representation are exceptional.

$\ell$ Reduction type Serre weight Serre conductor
$3$ good $2$ \( 1 \)
$19$ split multiplicative $20$ \( 1 \)

Isogenies

gp: ellisomat(E)
 

This curve has non-trivial cyclic isogenies of degree $d$ for $d=$ 3.
Its isogeny class 19.a consists of 3 curves linked by isogenies of degrees dividing 9.

Twists

This elliptic curve is its own minimal quadratic twist.

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
$2$ \(\Q(\sqrt{-3}) \) \(\Z/3\Z \oplus \Z/3\Z\) 2.0.3.1-361.2-a4
$3$ 3.1.76.1 \(\Z/6\Z\) not in database
$6$ 6.0.109744.2 \(\Z/2\Z \oplus \Z/6\Z\) not in database
$6$ 6.0.155952.1 \(\Z/3\Z \oplus \Z/6\Z\) not in database
$9$ 9.3.1270238787.1 \(\Z/9\Z\) not in database
$12$ 12.2.937292452593664.2 \(\Z/12\Z\) not in database
$12$ 12.0.8779890495744.1 \(\Z/6\Z \oplus \Z/6\Z\) not in database
$18$ 18.0.358752951832597688547.1 \(\Z/3\Z \oplus \Z/9\Z\) not in database
$18$ 18.0.16877848680315122776257224907.2 \(\Z/3\Z \oplus \Z/9\Z\) not in database
$18$ 18.0.43564677551979246963.1 \(\Z/3\Z \oplus \Z/9\Z\) not in database

We only show fields where the torsion growth is primitive.

Iwasawa invariants

$p$ 2 3 19
Reduction type ss ord split
$\lambda$-invariant(s) 0,3 0 1
$\mu$-invariant(s) 0,0 1 0

All Iwasawa $\lambda$ and $\mu$-invariants for primes $p\ge 5$ of good reduction are zero.

$p$-adic regulators

All $p$-adic regulators are identically $1$ since the rank is $0$.