Abelian variety isogeny class 2.11.c_w over $\F_{11}$

• Label: 2.11.c_w
• Base field: $\F_{11}$
• Dimension: $2$
• $p$-rank: $1$
• Ordinary: no
• Supersingular: no
• Simple: no
• Geometrically simple: no
• Primitive: yes
• Principally polarizable: yes
• Contains a Jacobian: yes

Invariants

Base field:	$\F_{11}$
Dimension:	$2$
L-polynomial:	$( 1 + 11 x^{2} )( 1 + 2 x + 11 x^{2} )$
	$1 + 2 x + 22 x^{2} + 22 x^{3} + 121 x^{4}$
Frobenius angles:	$\pm0.5$, $\pm0.597491114521$
Angle rank:	$1$ (numerical)
Jacobians:	$12$

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:	$[0, 1/2, 1/2, 1]$

Point counts

Point counts of the abelian variety

$r$	$1$	$2$	$3$	$4$	$5$
$A(\F_{q^r})$	$168$	$20160$	$1696968$	$209664000$	$26066910408$

Point counts of the curve

$r$	$1$	$2$	$3$	$4$	$5$	$6$	$7$	$8$	$9$	$10$
$C(\F_{q^r})$	$14$	$162$	$1274$	$14318$	$161854$	$1773522$	$19479754$	$214352158$	$2357984174$	$25937425602$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 12 curves (of which all are hyperelliptic):

• $y^2=8 x^6+8 x^5+x^3+6 x+7$
• $y^2=5 x^6+3 x^5+4 x^4+8 x^3+4 x^2+3 x+5$
• $y^2=9 x^6+2 x^5+6 x^4+10 x^2+8 x+5$
• $y^2=3 x^6+3 x^5+x^4+6 x^3+x^2+3 x+3$
• $y^2=9 x^6+10 x^5+8 x^4+6 x^2+7 x+5$
• $y^2=8 x^6+3 x^5+8 x^4+x^3+8 x^2+3 x+8$
• $y^2=3 x^5+5 x^4+5 x^3+x^2+x$
• $y^2=9 x^6+6 x^5+2 x^4+4 x^3+2 x^2+6 x+9$
• $y^2=3 x^6+5 x^5+8 x^4+4 x^3+6 x^2+9 x+9$
• $y^2=10 x^6+9 x^5+x^4+6 x^3+x^2+9 x+10$
• $y^2=6 x^5+8 x^4+10 x^3+2 x^2+10 x$
• $y^2=6 x^6+2 x^5+3 x^4+2 x^3+3 x^2+2 x+6$

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{11^{2}}$.

Endomorphism algebra over $\F_{11}$

The isogeny class factors as 1.11.a $\times$ 1.11.c and its endomorphism algebra is a direct product of the endomorphism algebras for each isotypic factor. The endomorphism algebra for each factor is:

• 1.11.a : \(\Q(\sqrt{-11}) \).
• 1.11.c : \(\Q(\sqrt{-10}) \).

Endomorphism algebra over $\overline{\F}_{11}$

The base change of $A$ to $\F_{11^{2}}$ is 1.121.s $\times$ 1.121.w. The endomorphism algebra for each factor is:

• 1.121.s : \(\Q(\sqrt{-10}) \).
• 1.121.w : the quaternion algebra over \(\Q\) ramified at $11$ and $\infty$.

Base change

This is a primitive isogeny class.

Twists

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

Twist	Extension degree	Common base change
2.11.ac_w	$2$	2.121.bo_yo