# Properties

 Label 336.a4 Conductor $336$ Discriminant $-70837874688$ j-invariant $$-\frac{4354703137}{17294403}$$ CM no Rank $1$ Torsion structure $$\Z/{4}\Z$$

# Related objects

Show commands: Magma / Oscar / PariGP / SageMath

## Simplified equation

 $$y^2=x^3-x^2-544x+13888$$ y^2=x^3-x^2-544x+13888 (homogenize, simplify) $$y^2z=x^3-x^2z-544xz^2+13888z^3$$ y^2z=x^3-x^2z-544xz^2+13888z^3 (dehomogenize, simplify) $$y^2=x^3-44091x+9992106$$ y^2=x^3-44091x+9992106 (homogenize, minimize)

comment: Define the curve

sage: E = EllipticCurve([0, -1, 0, -544, 13888])

gp: E = ellinit([0, -1, 0, -544, 13888])

magma: E := EllipticCurve([0, -1, 0, -544, 13888]);

oscar: E = EllipticCurve([0, -1, 0, -544, 13888])

sage: E.short_weierstrass_model()

magma: WeierstrassModel(E);

oscar: short_weierstrass_model(E)

## Mordell-Weil group structure

$$\Z \oplus \Z/{4}\Z$$

magma: MordellWeilGroup(E);

### Infinite order Mordell-Weil generator and height

 $P$ = $$\left(32, 168\right)$$ (32, 168) $\hat{h}(P)$ ≈ $0.74629920869451370890943760363$

sage: E.gens()

magma: Generators(E);

gp: E.gen

## Torsion generators

$$\left(18, 98\right)$$

comment: Torsion subgroup

sage: E.torsion_subgroup().gens()

gp: elltors(E)

magma: TorsionSubgroup(E);

oscar: torsion_structure(E)

## Integral points

$$\left(-31, 0\right)$$, $$(-24,\pm 112)$$, $$(-6,\pm 130)$$, $$(18,\pm 98)$$, $$(32,\pm 168)$$, $$(312,\pm 5488)$$

comment: Integral points

sage: E.integral_points()

magma: IntegralPoints(E);

## Invariants

 Conductor: $$336$$ = $2^{4} \cdot 3 \cdot 7$ comment: Conductor  sage: E.conductor().factor()  gp: ellglobalred(E)[1]  magma: Conductor(E);  oscar: conductor(E) Discriminant: $-70837874688$ = $-1 \cdot 2^{12} \cdot 3 \cdot 7^{8}$ comment: Discriminant  sage: E.discriminant().factor()  gp: E.disc  magma: Discriminant(E);  oscar: discriminant(E) j-invariant: $$-\frac{4354703137}{17294403}$$ = $-1 \cdot 3^{-1} \cdot 7^{-8} \cdot 23^{3} \cdot 71^{3}$ comment: j-invariant  sage: E.j_invariant().factor()  gp: E.j  magma: jInvariant(E);  oscar: j_invariant(E) Endomorphism ring: $\Z$ Geometric endomorphism ring: $$\Z$$ (no potential complex multiplication) sage: E.has_cm()  magma: HasComplexMultiplication(E); Sato-Tate group: $\mathrm{SU}(2)$ Faltings height: $0.76735256395088508017549797613\dots$ gp: ellheight(E)  magma: FaltingsHeight(E);  oscar: faltings_height(E) Stable Faltings height: $0.074205383390939770758265854672\dots$ magma: StableFaltingsHeight(E);  oscar: stable_faltings_height(E)

## BSD invariants

 Analytic rank: $1$ sage: E.analytic_rank()  gp: ellanalyticrank(E)  magma: AnalyticRank(E); Regulator: $0.74629920869451370890943760363\dots$ comment: Regulator  sage: E.regulator()  G = E.gen \\ if available matdet(ellheightmatrix(E,G))  magma: Regulator(E); Real period: $0.95549489037591459827657410938\dots$ 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: $32$  = $2^{2}\cdot1\cdot2^{3}$ 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: $4$ comment: Torsion order  sage: E.torsion_order()  gp: elltors(E)[1]  magma: Order(TorsionSubgroup(E));  oscar: prod(torsion_structure(E)[1]) Analytic order of Ш: $1$ (exact) comment: Order of Sha  sage: E.sha().an_numerical()  magma: MordellWeilShaInformation(E); Special value: $L'(E,1)$ ≈ $1.4261701611983923742568767354$ 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);

## BSD formula

$\displaystyle 1.426170161 \approx L'(E,1) = \frac{\# Ш(E/\Q)\cdot \Omega_E \cdot \mathrm{Reg}(E/\Q) \cdot \prod_p c_p}{\#E(\Q)_{\rm tor}^2} \approx \frac{1 \cdot 0.955495 \cdot 0.746299 \cdot 32}{4^2} \approx 1.426170161$

# 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 analyiic 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

$$q - q^{3} - 2 q^{5} + q^{7} + q^{9} - 4 q^{11} - 2 q^{13} + 2 q^{15} - 6 q^{17} - 4 q^{19} + O(q^{20})$$

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);

Modular degree: 256
comment: Modular degree

sage: E.modular_degree()

gp: ellmoddegree(E)

magma: ModularDegree(E);

$\Gamma_0(N)$-optimal: no
Manin constant: 1
comment: Manin constant

magma: ManinConstant(E);

## Local data

This elliptic curve is not semistable. There are 3 primes of bad reduction:

prime Tamagawa number Kodaira symbol Reduction type Root number ord($N$) ord($\Delta$) ord$(j)_{-}$
$2$ $4$ $I_{4}^{*}$ Additive -1 4 12 0
$3$ $1$ $I_{1}$ Non-split multiplicative 1 1 1 1
$7$ $8$ $I_{8}$ Split multiplicative -1 1 8 8

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
$2$ 2B 8.48.0.161

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 = [[5, 4, 332, 333], [241, 16, 248, 129], [1, 16, 0, 1], [232, 1, 191, 10], [15, 2, 238, 323], [281, 320, 282, 263], [321, 16, 320, 17], [1, 0, 16, 1], [13, 16, 164, 105]]

GL(2,Integers(336)).subgroup(gens)

Gens := [[5, 4, 332, 333], [241, 16, 248, 129], [1, 16, 0, 1], [232, 1, 191, 10], [15, 2, 238, 323], [281, 320, 282, 263], [321, 16, 320, 17], [1, 0, 16, 1], [13, 16, 164, 105]];

sub<GL(2,Integers(336))|Gens>;

The image $H:=\rho_E(\Gal(\overline{\Q}/\Q))$ of the adelic Galois representation has level $$336 = 2^{4} \cdot 3 \cdot 7$$, index $192$, genus $1$, and generators

$\left(\begin{array}{rr} 5 & 4 \\ 332 & 333 \end{array}\right),\left(\begin{array}{rr} 241 & 16 \\ 248 & 129 \end{array}\right),\left(\begin{array}{rr} 1 & 16 \\ 0 & 1 \end{array}\right),\left(\begin{array}{rr} 232 & 1 \\ 191 & 10 \end{array}\right),\left(\begin{array}{rr} 15 & 2 \\ 238 & 323 \end{array}\right),\left(\begin{array}{rr} 281 & 320 \\ 282 & 263 \end{array}\right),\left(\begin{array}{rr} 321 & 16 \\ 320 & 17 \end{array}\right),\left(\begin{array}{rr} 1 & 0 \\ 16 & 1 \end{array}\right),\left(\begin{array}{rr} 13 & 16 \\ 164 & 105 \end{array}\right)$.

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

The torsion field $K:=\Q(E[336])$ is a degree-$12386304$ Galois extension of $\Q$ with $\Gal(K/\Q)$ isomorphic to the projection of $H$ to $\GL_2(\Z/336\Z)$.

## Isogenies

gp: ellisomat(E)

This curve has non-trivial cyclic isogenies of degree $d$ for $d=$ 2, 4 and 8.
Its isogeny class 336.a consists of 6 curves linked by isogenies of degrees dividing 8.

## Twists

The minimal quadratic twist of this elliptic curve is 21.a4, its twist by $-4$.

## 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 $E(\Q)_{\rm tors}$ $\cong \Z/{4}\Z$ are as follows:

 $[K:\Q]$ $E(K)_{\rm tors}$ Base change curve $K$ $2$ $$\Q(\sqrt{-3})$$ $$\Z/2\Z \oplus \Z/4\Z$$ 2.0.3.1-37632.2-f2 $2$ $$\Q(\sqrt{2})$$ $$\Z/8\Z$$ Not in database $2$ $$\Q(\sqrt{-6})$$ $$\Z/8\Z$$ Not in database $4$ $$\Q(\sqrt{2}, \sqrt{-3})$$ $$\Z/2\Z \oplus \Z/8\Z$$ Not in database $8$ 8.0.2985984.1 $$\Z/4\Z \oplus \Z/4\Z$$ Not in database $8$ 8.0.47775744.1 $$\Z/2\Z \oplus \Z/8\Z$$ Not in database $8$ 8.4.362538860544.5 $$\Z/16\Z$$ Not in database $8$ 8.0.7341411926016.73 $$\Z/16\Z$$ Not in database $8$ 8.2.108884466432.1 $$\Z/12\Z$$ Not in database $16$ 16.0.36520347436056576.1 $$\Z/4\Z \oplus \Z/8\Z$$ Not in database $16$ 16.0.328683126924509184.2 $$\Z/4\Z \oplus \Z/8\Z$$ Not in database $16$ deg 16 $$\Z/2\Z \oplus \Z/16\Z$$ Not in database $16$ deg 16 $$\Z/2\Z \oplus \Z/16\Z$$ Not in database $16$ deg 16 $$\Z/2\Z \oplus \Z/12\Z$$ Not in database $16$ deg 16 $$\Z/24\Z$$ Not in database $16$ deg 16 $$\Z/24\Z$$ Not in database

We only show fields where the torsion growth is primitive. For fields not in the database, click on the degree shown to reveal the defining polynomial.

## Iwasawa invariants

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

## $p$-adic regulators

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