Properties

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

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Invariants

Base field:  $\F_{11}$
Dimension:  $2$
L-polynomial:  $1 - x + 11 x^{2} - 11 x^{3} + 121 x^{4}$
Frobenius angles:  $\pm0.302650775488$, $\pm0.641582372415$
Angle rank:  $2$ (numerical)
Number field:  \(\Q(\sqrt{-130 -6 \sqrt{5}})\)
Galois group:  $D_{4}$
Jacobians:  $12$
Cyclic group of points:    yes

This isogeny class is simple and geometrically 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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $121$ $17545$ $1767931$ $217926445$ $26035000816$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $11$ $143$ $1331$ $14883$ $161656$ $1766963$ $19478701$ $214378483$ $2357936801$ $25937661398$

Jacobians and polarizations

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

  • $y^2=2 x^6+5 x^5+8 x^4+2 x^3+x^2+8 x$
  • $y^2=3 x^6+3 x^5+4 x^4+6 x^3+8 x^2+4 x+6$
  • $y^2=5 x^6+6 x^5+6 x^4+4 x^2+5 x+6$
  • $y^2=x^6+7 x^5+9 x^4+8 x^3+x+10$
  • $y^2=5 x^5+2 x^4+8 x^3+9 x^2+1$
  • $y^2=5 x^6+7 x^4+5 x^3+3 x^2+10 x+6$
  • $y^2=7 x^6+x^5+9 x^4+4 x^3+10 x^2+5 x+9$
  • $y^2=6 x^5+6 x^4+9 x^3+x^2+x+3$
  • $y^2=7 x^6+3 x^5+9 x^4+8 x^3+4 x^2+9 x+2$
  • $y^2=7 x^6+5 x^5+6 x^4+2 x^3+2 x^2+8 x+2$
  • $y^2=10 x^6+5 x^5+9 x^3+6 x^2+6 x$
  • $y^2=2 x^5+7 x^3+8 x^2+6 x+9$

Decomposition and endomorphism algebra

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

Endomorphism algebra over $\F_{11}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-130 -6 \sqrt{5}})\).

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.11.b_l$2$2.121.v_nd