Abelian variety isogeny class 3.2.ad_g_ai over $\F_{2}$

• Label: 3.2.ad_g_ai
• Base field: $\F_{2}$
• Dimension: $3$
• $p$-rank: $1$
• Ordinary: no
• Supersingular: no
• Simple: no
• Geometrically simple: no
• Primitive: yes
• Principally polarizable: yes
• Contains a Jacobian: yes

Invariants

Base field:	$\F_{2}$
Dimension:	$3$
L-polynomial:	$( 1 + x + 2 x^{2} )( 1 - 2 x + 2 x^{2} )^{2}$
	$1 - 3 x + 6 x^{2} - 8 x^{3} + 12 x^{4} - 12 x^{5} + 8 x^{6}$
Frobenius angles:	$\pm0.250000000000$, $\pm0.250000000000$, $\pm0.615026728081$
Angle rank:	$1$ (numerical)
Jacobians:	$1$

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

Newton polygon

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

Point counts

Point counts of the abelian variety

$r$	$1$	$2$	$3$	$4$	$5$
$A(\F_{q^r})$	$4$	$200$	$676$	$10000$	$73964$

Point counts of the curve

$r$	$1$	$2$	$3$	$4$	$5$	$6$	$7$	$8$	$9$	$10$
$C(\F_{q^r})$	$0$	$8$	$12$	$32$	$60$	$56$	$84$	$224$	$444$	$968$

Jacobians and polarizations

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

• $y^2+(x^4+x^2+1)y=x^8+x+1$

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^2 $\times$ 1.2.b and its endomorphism algebra is a direct product of the endomorphism algebras for each isotypic factor. The endomorphism algebra for each factor is:

• 1.2.ac^2 : $\mathrm{M}_{2}($\(\Q(\sqrt{-1}) \)$)$
• 1.2.b : \(\Q(\sqrt{-7}) \).

Endomorphism algebra over $\overline{\F}_{2}$

The base change of $A$ to $\F_{2^{4}}$ is 1.16.ab $\times$ 1.16.i^2. The endomorphism algebra for each factor is:

• 1.16.ab : \(\Q(\sqrt{-7}) \).
• 1.16.i^2 : $\mathrm{M}_{2}(B)$, where $B$ is the quaternion algebra over \(\Q\) ramified at $2$ and $\infty$.

Remainder of endomorphism lattice by field

• Endomorphism algebra over $\F_{2^{2}}$
  The base change of $A$ to $\F_{2^{2}}$ is 1.4.a^2 $\times$ 1.4.d. The endomorphism algebra for each factor is:

  • 1.4.a^2 : $\mathrm{M}_{2}($\(\Q(\sqrt{-1}) \)$)$
  • 1.4.d : \(\Q(\sqrt{-7}) \).

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
3.2.af_o_ay	$2$	3.4.d_m_y
3.2.ab_c_a	$2$	3.4.d_m_y
3.2.b_c_a	$2$	3.4.d_m_y
3.2.d_g_i	$2$	3.4.d_m_y
3.2.f_o_y	$2$	3.4.d_m_y
3.2.d_g_k	$3$	3.8.d_a_abg