Abelian variety isogeny class 4.4.ak_bx_agb_oa over $\F_{2^{2}}$

• Label: 4.4.ak_bx_agb_oa
• Base field: $\F_{2^{2}}$
• Dimension: $4$
• $p$-rank: $3$
• Ordinary: no
• Supersingular: no
• Simple: no
• Geometrically simple: no
• Primitive: yes
• Principally polarizable: yes
• Contains a Jacobian: no

Invariants

Base field:	$\F_{2^{2}}$
Dimension:	$4$
L-polynomial:	$( 1 - 2 x )^{2}( 1 - 6 x + 21 x^{2} - 49 x^{3} + 84 x^{4} - 96 x^{5} + 64 x^{6} )$
	$1 - 10 x + 49 x^{2} - 157 x^{3} + 364 x^{4} - 628 x^{5} + 784 x^{6} - 640 x^{7} + 256 x^{8}$
Frobenius angles:	$0$, $0$, $\pm0.155504948432$, $\pm0.300378009331$, $\pm0.490400327376$
Angle rank:	$3$ (numerical)

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

$r$	$1$	$2$	$3$	$4$	$5$
$A(\F_{q^r})$	$19$	$54891$	$16541077$	$3854720475$	$1073789714869$

Point counts of the (virtual) curve

$r$	$1$	$2$	$3$	$4$	$5$	$6$	$7$	$8$	$9$	$10$
$C(\F_{q^r})$	$-5$	$15$	$64$	$231$	$1000$	$4116$	$16186$	$64743$	$261775$	$1050180$

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 $\F_{2^{2}}$.

Endomorphism algebra over $\F_{2^{2}}$

The isogeny class factors as 1.4.ae $\times$ 3.4.ag_v_abx and its endomorphism algebra is a direct product of the endomorphism algebras for each isotypic factor. The endomorphism algebra for each factor is:

• 1.4.ae : the quaternion algebra over \(\Q\) ramified at $2$ and $\infty$.
• 3.4.ag_v_abx : 6.0.3877551.1.

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

Twist	Extension degree	Common base change
4.4.ac_b_l_abc	$2$	(not in LMFDB)
4.4.c_b_al_abc	$2$	(not in LMFDB)
4.4.k_bx_gb_oa	$2$	(not in LMFDB)
4.4.ae_n_abf_cs	$3$	(not in LMFDB)