Genus 2 curve 3860.a.77200.1

• Label: 3860.a.77200.1
• Conductor: $3860$
• Discriminant: $-77200$
• Mordell-Weil group: \(\Z \oplus \Z/{3}\Z\)
• Sato-Tate group: $\mathrm{USp}(4)$
• \(\End(J_{\overline{\Q}}) \otimes \R\): \(\R\)
• \(\End(J_{\overline{\Q}}) \otimes \Q\): \(\Q\)
• \(\End(J) \otimes \Q\): \(\Q\)
• \(\overline{\Q}\)-simple: yes
• \(\mathrm{GL}_2\)-type: no

Minimal equation

$y^2 + x^3y = 4x^2 - 4x + 1$

(, )

Invariants

Conductor:	\( N \)	\(=\)	\(3860\)	\(=\)	\( 2^{2} \cdot 5 \cdot 193 \)
Discriminant:	\( \Delta \)	\(=\)	\(-77200\)	\(=\)	\( - 2^{4} \cdot 5^{2} \cdot 193 \)

Igusa-Clebsch invariants

\( I_2 \)	\(=\)	\(120\)	\(=\)	\( 2^{3} \cdot 3 \cdot 5 \)
\( I_4 \)	\(=\)	\(3477\)	\(=\)	\( 3 \cdot 19 \cdot 61 \)
\( I_6 \)	\(=\)	\(133257\)	\(=\)	\( 3 \cdot 43 \cdot 1033 \)
\( I_{10} \)	\(=\)	\(9650\)	\(=\)	\( 2 \cdot 5^{2} \cdot 193 \)

Automorphism group

\(\mathrm{Aut}(X)\)	\(\simeq\)	$C_2$
\(\mathrm{Aut}(X_{\overline{\Q}})\)	\(\simeq\)	$C_2$

Rational points

All points
\((1 : 0 : 0)\)	\((1 : -1 : 0)\)	\((0 : -1 : 1)\)	\((0 : 1 : 1)\)	\((1 : 0 : 2)\)	\((1 : -1 : 2)\)
\((2 : 1 : 1)\)	\((2 : -9 : 1)\)

Number of rational Weierstrass points: \(0\)

This curve is locally solvable everywhere.

Mordell-Weil group of the Jacobian

Group structure: \(\Z \oplus \Z/{3}\Z\)

Generator	$D_0$						Height	Order
\((1 : -1 : 2) + (2 : 1 : 1) - (1 : -1 : 0) - (1 : 0 : 0)\)	\((x - 2z) (2x - z)\)	\(=\)	\(0,\)	\(4y\)	\(=\)	\(3xz^2 - 2z^3\)	\(0.043869\)	\(\infty\)
\(2 \cdot(0 : -1 : 1) - (1 : -1 : 0) - (1 : 0 : 0)\)	\(x^2\)	\(=\)	\(0,\)	\(y\)	\(=\)	\(2xz^2 - z^3\)	\(0\)	\(3\)

2-torsion field: 6.0.49408.1

BSD invariants

Hasse-Weil conjecture:	unverified
Analytic rank:	\(1\)
Mordell-Weil rank:	\(1\)
2-Selmer rank:	\(1\)
Regulator:	\( 0.043869 \)
Real period:	\( 18.56682 \)
Tamagawa product:	\( 6 \)
Torsion order:	\( 3 \)
Leading coefficient:	\( 0.543012 \)
Analytic order of Ш:	\( 1 \)   (rounded)
Order of Ш:	square

Local invariants

Prime	ord(\(N\))	ord(\(\Delta\))	Tamagawa	L-factor	Cluster picture
\(2\)	\(2\)	\(4\)	\(3\)	\(1 + 2 T^{2}\)
\(5\)	\(1\)	\(2\)	\(2\)	\(( 1 - T )( 1 + 3 T + 5 T^{2} )\)
\(193\)	\(1\)	\(1\)	\(1\)	\(( 1 - T )( 1 - 5 T + 193 T^{2} )\)

Galois representations

The mod-$\ell$ Galois representation has maximal image \(\GSp(4,\F_\ell)\) for all primes \( \ell \) except those listed.

Prime \(\ell\)	mod-\(\ell\) image	Is torsion prime?
\(2\)	2.10.1	no
\(3\)	3.80.1	yes

Sato-Tate group

\(\mathrm{ST}\)	\(\simeq\)	$\mathrm{USp}(4)$
\(\mathrm{ST}^0\)	\(\simeq\)	\(\mathrm{USp}(4)\)

Decomposition of the Jacobian

Simple over \(\overline{\Q}\)

Endomorphisms of the Jacobian

Not of \(\GL_2\)-type over \(\Q\)

Endomorphism ring over \(\Q\):

\(\End (J_{})\)	\(\simeq\)	\(\Z\)
\(\End (J_{}) \otimes \Q \)	\(\simeq\)	\(\Q\)
\(\End (J_{}) \otimes \R\)	\(\simeq\)	\(\R\)

All \(\overline{\Q}\)-endomorphisms of the Jacobian are defined over \(\Q\).