Properties

Label 2.8.ac_ad
Base field $\F_{2^{3}}$
Dimension $2$
$p$-rank $2$
Ordinary yes
Supersingular no
Simple yes
Geometrically simple yes
Primitive no
Principally polarizable yes
Contains a Jacobian yes

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Invariants

Base field:  $\F_{2^{3}}$
Dimension:  $2$
L-polynomial:  $1 - 2 x - 3 x^{2} - 16 x^{3} + 64 x^{4}$
Frobenius angles:  $\pm0.0815683182843$, $\pm0.710356941346$
Angle rank:  $2$ (numerical)
Number field:  4.0.1025.1
Galois group:  $D_{4}$
Jacobians:  $10$
Isomorphism classes:  20

This isogeny class is simple and geometrically simple, not 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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $44$ $3520$ $226556$ $16966400$ $1068504844$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $7$ $55$ $439$ $4143$ $32607$ $261415$ $2100679$ $16776543$ $134225647$ $1073858775$

Jacobians and polarizations

This isogeny class contains the Jacobians of 10 curves (of which all are hyperelliptic), and hence is principally polarizable:

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{2^{3}}$.

Endomorphism algebra over $\F_{2^{3}}$
The endomorphism algebra of this simple isogeny class is 4.0.1025.1.

Base change

This isogeny class is not primitive. It is a base change from the following isogeny classes over subfields of $\F_{2^{3}}$.

SubfieldPrimitive Model
$\F_{2}$2.2.b_d

Twists

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

TwistExtension degreeCommon base change
2.8.c_ad$2$2.64.ak_cv