Properties

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

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Invariants

Base field:  $\F_{2^{3}}$
Dimension:  $2$
L-polynomial:  $( 1 - 5 x + 8 x^{2} )( 1 + 3 x + 8 x^{2} )$
  $1 - 2 x + x^{2} - 16 x^{3} + 64 x^{4}$
Frobenius angles:  $\pm0.154919815756$, $\pm0.677932000632$
Angle rank:  $2$ (numerical)
Jacobians:  $12$
Isomorphism classes:  102

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $48$ $4032$ $237744$ $17305344$ $1086883248$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $7$ $63$ $463$ $4223$ $33167$ $262143$ $2101967$ $16785151$ $134203279$ $1073782143$

Jacobians and polarizations

This isogeny class contains the Jacobians of 12 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 isogeny class factors as 1.8.af $\times$ 1.8.d 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 is a list of all twists of this isogeny class.

TwistExtension degreeCommon base change
2.8.ai_bf$2$2.64.ac_cn
2.8.c_b$2$2.64.ac_cn
2.8.i_bf$2$2.64.ac_cn