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

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

Invariants

Base field:	$\F_{11}$
Dimension:	$2$
L-polynomial:	$1 - 18 x^{2} + 121 x^{4}$
Frobenius angles:	$\pm0.0974911145211$, $\pm0.902508885479$
Angle rank:	$1$ (numerical)
Number field:	\(\Q(i, \sqrt{10})\)
Galois group:	$C_2^2$
Jacobians:	$3$
Isomorphism classes:	18

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

Newton polygon

This isogeny class is ordinary.

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

Point counts

Point counts of the abelian variety

$r$	$1$	$2$	$3$	$4$	$5$
$A(\F_{q^r})$	$104$	$10816$	$1772264$	$211993600$	$25937745704$

Point counts of the curve

$r$	$1$	$2$	$3$	$4$	$5$	$6$	$7$	$8$	$9$	$10$
$C(\F_{q^r})$	$12$	$86$	$1332$	$14478$	$161052$	$1772966$	$19487172$	$214403998$	$2357947692$	$25938066806$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 3 curves (of which all are hyperelliptic):

• $y^2=2 x^6+7 x^5+x^4+6 x^3+8 x^2+2 x+1$
• $y^2=2 x^6+6 x^5+3 x^4+9 x^3+2 x^2+9 x+7$
• $y^2=2 x^6+5 x^5+3 x^4+x^2+8 x+7$

Decomposition and endomorphism algebra

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

Endomorphism algebra over $\F_{11}$

The endomorphism algebra of this simple isogeny class is \(\Q(i, \sqrt{10})\).

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

The base change of $A$ to $\F_{11^{2}}$ is 1.121.as^2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-10}) \)$)$

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
2.11.ae_ba	$4$	(not in LMFDB)
2.11.a_s	$4$	(not in LMFDB)
2.11.e_ba	$4$	(not in LMFDB)