Properties

Label 2.8.aj_bj
Base field $\F_{2^{3}}$
Dimension $2$
$p$-rank $2$
Ordinary yes
Supersingular no
Simple yes
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:  $1 - 9 x + 35 x^{2} - 72 x^{3} + 64 x^{4}$
Frobenius angles:  $\pm0.0373126015494$, $\pm0.296020731784$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{-3}, \sqrt{5})\)
Galois group:  $C_2^2$
Jacobians:  $1$
Isomorphism classes:  1

This isogeny class is simple but not geometrically 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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $19$ $3439$ $261364$ $16744491$ $1064657989$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $0$ $54$ $513$ $4090$ $32490$ $260583$ $2092356$ $16769074$ $134217729$ $1073781414$

Jacobians and polarizations

This isogeny class contains the Jacobian of 1 curve (which is hyperelliptic), and hence is principally polarizable:

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{2^{18}}$.

Endomorphism algebra over $\F_{2^{3}}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-3}, \sqrt{5})\).
Endomorphism algebra over $\overline{\F}_{2^{3}}$
The base change of $A$ to $\F_{2^{18}}$ is 1.262144.abeb 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-15}) \)$)$
Remainder of endomorphism lattice by field

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.8.j_bj$2$2.64.al_cf
2.8.a_l$3$2.512.a_abeb
2.8.j_bj$3$2.512.a_abeb

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

TwistExtension degreeCommon base change
2.8.j_bj$2$2.64.al_cf
2.8.a_l$3$2.512.a_abeb
2.8.j_bj$3$2.512.a_abeb
2.8.a_al$12$(not in LMFDB)