Properties

Label 4.2.af_p_abf_by
Base field $\F_{2}$
Dimension $4$
$p$-rank $3$
Ordinary no
Supersingular no
Simple no
Geometrically simple no
Primitive yes
Principally polarizable yes
Contains a Jacobian no

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Invariants

Base field:  $\F_{2}$
Dimension:  $4$
L-polynomial:  $( 1 - 2 x + 2 x^{2} )( 1 - x + 2 x^{2} )( 1 - 2 x + 3 x^{2} - 4 x^{3} + 4 x^{4} )$
  $1 - 5 x + 15 x^{2} - 31 x^{3} + 50 x^{4} - 62 x^{5} + 60 x^{6} - 40 x^{7} + 16 x^{8}$
Frobenius angles:  $\pm0.174442860055$, $\pm0.250000000000$, $\pm0.384973271919$, $\pm0.546783656212$
Angle rank:  $3$ (numerical)
Jacobians:  $0$
Isomorphism classes:  4

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

Newton polygon

$p$-rank:  $3$
Slopes:  $[0, 0, 0, 1/2, 1/2, 1, 1, 1]$

Point counts

Point counts of the abelian variety

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $4$ $1120$ $11284$ $89600$ $1589324$

Point counts of the (virtual) curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $-2$ $10$ $16$ $22$ $48$ $82$ $124$ $254$ $520$ $930$

Jacobians and polarizations

This isogeny class is principally polarizable, but does not contain a Jacobian.

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{2^{4}}$.

Endomorphism algebra over $\F_{2}$
The isogeny class factors as 1.2.ac $\times$ 1.2.ab $\times$ 2.2.ac_d 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 $\overline{\F}_{2}$
The base change of $A$ to $\F_{2^{4}}$ is 1.16.ab $\times$ 1.16.i $\times$ 2.16.ac_b. The endomorphism algebra for each factor is:
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
4.2.ad_h_an_w$2$4.4.f_p_bn_dk
4.2.ab_d_ad_g$2$4.4.f_p_bn_dk
4.2.ab_d_b_c$2$4.4.f_p_bn_dk
4.2.b_d_ab_c$2$4.4.f_p_bn_dk
4.2.b_d_d_g$2$4.4.f_p_bn_dk
4.2.d_h_n_w$2$4.4.f_p_bn_dk
4.2.f_p_bf_by$2$4.4.f_p_bn_dk

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

TwistExtension degreeCommon base change
4.2.ad_h_an_w$2$4.4.f_p_bn_dk
4.2.ab_d_ad_g$2$4.4.f_p_bn_dk
4.2.ab_d_b_c$2$4.4.f_p_bn_dk
4.2.b_d_ab_c$2$4.4.f_p_bn_dk
4.2.b_d_d_g$2$4.4.f_p_bn_dk
4.2.d_h_n_w$2$4.4.f_p_bn_dk
4.2.f_p_bf_by$2$4.4.f_p_bn_dk
4.2.b_d_ab_c$4$(not in LMFDB)
4.2.ad_j_ar_bc$8$(not in LMFDB)
4.2.ab_f_ah_m$8$(not in LMFDB)
4.2.b_f_h_m$8$(not in LMFDB)
4.2.d_j_r_bc$8$(not in LMFDB)