Properties

Label 2.7.ac_l
Base field $\F_{7}$
Dimension $2$
$p$-rank $2$
Ordinary yes
Supersingular no
Simple no
Geometrically simple no
Primitive yes
Principally polarizable yes
Contains a Jacobian yes

Related objects

Downloads

Learn more

Invariants

Base field:  $\F_{7}$
Dimension:  $2$
L-polynomial:  $( 1 - 3 x + 7 x^{2} )( 1 + x + 7 x^{2} )$
  $1 - 2 x + 11 x^{2} - 14 x^{3} + 49 x^{4}$
Frobenius angles:  $\pm0.308124534521$, $\pm0.560518859162$
Angle rank:  $2$ (numerical)
Jacobians:  $8$

This isogeny class is not simple, primitive, ordinary, and not supersingular. It is principally polarizable and contains a Jacobian.

Newton polygon

This isogeny class is ordinary.

$p$-rank:  $2$
Slopes:  $[0, 0, 1, 1]$

Point counts

Point counts of the abelian variety

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $45$ $3465$ $123120$ $5769225$ $285493725$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $6$ $68$ $360$ $2404$ $16986$ $117326$ $820182$ $5764036$ $40375800$ $282496868$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 8 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{7}$.

Endomorphism algebra over $\F_{7}$
The isogeny class factors as 1.7.ad $\times$ 1.7.b and its endomorphism algebra is a direct product of the endomorphism algebras for each isotypic factor. The endomorphism algebra for each factor is:

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.7.ae_r$2$2.49.s_gh
2.7.c_l$2$2.49.s_gh
2.7.e_r$2$2.49.s_gh
2.7.ai_bd$3$2.343.q_abi
2.7.b_c$3$2.343.q_abi

Below is a list of all twists of this isogeny class.

TwistExtension degreeCommon base change
2.7.ae_r$2$2.49.s_gh
2.7.c_l$2$2.49.s_gh
2.7.e_r$2$2.49.s_gh
2.7.ai_bd$3$2.343.q_abi
2.7.b_c$3$2.343.q_abi
2.7.ah_ba$6$(not in LMFDB)
2.7.ac_ab$6$(not in LMFDB)
2.7.ab_c$6$(not in LMFDB)
2.7.c_ab$6$(not in LMFDB)
2.7.h_ba$6$(not in LMFDB)
2.7.i_bd$6$(not in LMFDB)