Properties

Label 2.4.ab_g
Base Field $\F_{2^{2}}$
Dimension $2$
Ordinary No
$p$-rank $1$
Principally polarizable Yes
Contains a Jacobian Yes

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Invariants

Base field:  $\F_{2^{2}}$
Dimension:  $2$
L-polynomial:  $( 1 - 2 x + 4 x^{2} )( 1 + x + 4 x^{2} )$
Frobenius angles:  $\pm0.333333333333$, $\pm0.580430623255$
Angle rank:  $1$ (numerical)
Jacobians:  2

This isogeny class is not simple.

Newton polygon

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

Point counts

This isogeny class contains the Jacobians of 2 curves, and hence is principally polarizable:

Point counts of the abelian variety

$r$ 1 2 3 4 5 6 7 8 9 10
$A(\F_{q^r})$ 18 504 4374 65520 1078398 16288776 262290438 4326547680 69193972494 1098831485304

Point counts of the curve

$r$ 1 2 3 4 5 6 7 8 9 10
$C(\F_{q^r})$ 4 28 70 256 1054 3976 16006 66016 263950 1047928

Decomposition and endomorphism algebra

Endomorphism algebra over $\F_{2^{2}}$
The isogeny class factors as 1.4.ac $\times$ 1.4.b and its endomorphism algebra is a direct product of the endomorphism algebras for each isotypic factor. The endomorphism algebra for each factor is:
Endomorphism algebra over $\overline{\F}_{2^{2}}$
The base change of $A$ to $\F_{2^{6}}$ is 1.64.al $\times$ 1.64.q. The endomorphism algebra for each factor is:
All geometric endomorphisms are defined over $\F_{2^{6}}$.

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.
TwistExtension DegreeCommon base change
2.4.ad_k$2$2.16.l_ci
2.4.b_g$2$2.16.l_ci
2.4.d_k$2$2.16.l_ci
2.4.f_m$3$2.64.f_abw
Below is a list of all twists of this isogeny class.
TwistExtension DegreeCommon base change
2.4.ad_k$2$2.16.l_ci
2.4.b_g$2$2.16.l_ci
2.4.d_k$2$2.16.l_ci
2.4.f_m$3$2.64.f_abw
2.4.af_m$6$(not in LMFDB)
2.4.ad_e$6$(not in LMFDB)
2.4.d_e$6$(not in LMFDB)
2.4.ab_i$12$(not in LMFDB)
2.4.b_i$12$(not in LMFDB)