# Properties

 Label 970.a.1940.1 Conductor $970$ Discriminant $1940$ Mordell-Weil group $$\Z/{10}\Z$$ 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

# Learn more

Show commands: SageMath / Magma

## Simplified equation

 $y^2 + (x + 1)y = x^5 + x^4 + x^3 + x^2$ (homogenize, simplify) $y^2 + (xz^2 + z^3)y = x^5z + x^4z^2 + x^3z^3 + x^2z^4$ (dehomogenize, simplify) $y^2 = 4x^5 + 4x^4 + 4x^3 + 5x^2 + 2x + 1$ (minimize, homogenize)

sage: R.<x> = PolynomialRing(QQ); C = HyperellipticCurve(R([0, 0, 1, 1, 1, 1]), R([1, 1]));

magma: R<x> := PolynomialRing(Rationals()); C := HyperellipticCurve(R![0, 0, 1, 1, 1, 1], R![1, 1]);

sage: X = HyperellipticCurve(R([1, 2, 5, 4, 4, 4]))

magma: X,pi:= SimplifiedModel(C);

## Invariants

 Conductor: $$N$$ $$=$$ $$970$$ $$=$$ $$2 \cdot 5 \cdot 97$$ magma: Conductor(LSeries(C)); Factorization($1); Discriminant: $$\Delta$$ $$=$$ $$1940$$ $$=$$ $$2^{2} \cdot 5 \cdot 97$$ magma: Discriminant(C); Factorization(Integers()!$1);

### G2 invariants

 $$I_2$$ $$=$$ $$24$$ $$=$$ $$2^{3} \cdot 3$$ $$I_4$$ $$=$$ $$684$$ $$=$$ $$2^{2} \cdot 3^{2} \cdot 19$$ $$I_6$$ $$=$$ $$4887$$ $$=$$ $$3^{3} \cdot 181$$ $$I_{10}$$ $$=$$ $$7760$$ $$=$$ $$2^{4} \cdot 5 \cdot 97$$ $$J_2$$ $$=$$ $$12$$ $$=$$ $$2^{2} \cdot 3$$ $$J_4$$ $$=$$ $$-108$$ $$=$$ $$- 2^{2} \cdot 3^{3}$$ $$J_6$$ $$=$$ $$-159$$ $$=$$ $$- 3 \cdot 53$$ $$J_8$$ $$=$$ $$-3393$$ $$=$$ $$- 3^{2} \cdot 13 \cdot 29$$ $$J_{10}$$ $$=$$ $$1940$$ $$=$$ $$2^{2} \cdot 5 \cdot 97$$ $$g_1$$ $$=$$ $$62208/485$$ $$g_2$$ $$=$$ $$-46656/485$$ $$g_3$$ $$=$$ $$-5724/485$$

sage: C.igusa_clebsch_invariants(); [factor(a) for a in _]

magma: IgusaClebschInvariants(C); IgusaInvariants(C); G2Invariants(C);

## Automorphism group

 $$\mathrm{Aut}(X)$$ $$\simeq$$ $C_2$ magma: AutomorphismGroup(C); IdentifyGroup($1); $$\mathrm{Aut}(X_{\overline{\Q}})$$ $$\simeq$$$C_2$magma: AutomorphismGroup(ChangeRing(C,AlgebraicClosure(Rationals()))); IdentifyGroup($1);

## Rational points

 All points: $$(1 : 0 : 0),\, (0 : 0 : 1),\, (-1 : 0 : 1),\, (0 : -1 : 1)$$ All points: $$(1 : 0 : 0),\, (0 : 0 : 1),\, (-1 : 0 : 1),\, (0 : -1 : 1)$$ All points: $$(1 : 0 : 0),\, (-1 : 0 : 1),\, (0 : -1 : 1),\, (0 : 1 : 1)$$

magma: [C![-1,0,1],C![0,-1,1],C![0,0,1],C![1,0,0]]; // minimal model

magma: [C![-1,0,1],C![0,-1,1],C![0,1,1],C![1,0,0]]; // simplified model

Number of rational Weierstrass points: $$2$$

magma: #Roots(HyperellipticPolynomials(SimplifiedModel(C)));

This curve is locally solvable everywhere.

magma: f,h:=HyperellipticPolynomials(C); g:=4*f+h^2; HasPointsEverywhereLocally(g,2) and (#Roots(ChangeRing(g,RealField())) gt 0 or LeadingCoefficient(g) gt 0);

## Mordell-Weil group of the Jacobian

Group structure: $$\Z/{10}\Z$$

magma: MordellWeilGroupGenus2(Jacobian(C));

Generator $D_0$ Height Order
$$(-1 : 0 : 1) + (0 : 0 : 1) - 2 \cdot(1 : 0 : 0)$$ $$x (x + z)$$ $$=$$ $$0,$$ $$y$$ $$=$$ $$0$$ $$0$$ $$10$$
Generator $D_0$ Height Order
$$(-1 : 0 : 1) + (0 : 0 : 1) - 2 \cdot(1 : 0 : 0)$$ $$x (x + z)$$ $$=$$ $$0,$$ $$y$$ $$=$$ $$0$$ $$0$$ $$10$$
Generator $D_0$ Height Order
$$(-1 : 0 : 1) + (0 : 1 : 1) - 2 \cdot(1 : 0 : 0)$$ $$x (x + z)$$ $$=$$ $$0,$$ $$y$$ $$=$$ $$xz^2 + z^3$$ $$0$$ $$10$$

## BSD invariants

 Hasse-Weil conjecture: unverified Analytic rank: $$0$$ Mordell-Weil rank: $$0$$ 2-Selmer rank: $$1$$ Regulator: $$1$$ Real period: $$17.37577$$ Tamagawa product: $$2$$ Torsion order: $$10$$ Leading coefficient: $$0.347515$$ Analytic order of Ш: $$1$$   (rounded) Order of Ш: square

## Local invariants

Prime ord($$N$$) ord($$\Delta$$) Tamagawa L-factor Cluster picture
$$2$$ $$1$$ $$2$$ $$2$$ $$( 1 - T )( 1 + 2 T + 2 T^{2} )$$
$$5$$ $$1$$ $$1$$ $$1$$ $$( 1 - T )( 1 + 4 T + 5 T^{2} )$$
$$97$$ $$1$$ $$1$$ $$1$$ $$( 1 + T )( 1 + 2 T + 97 T^{2} )$$

## 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 $$\Q$$.