Properties

Label 2.23.am_cs
Base field $\F_{23}$
Dimension $2$
$p$-rank $2$
Ordinary yes
Supersingular no
Simple yes
Geometrically simple yes
Primitive yes
Principally polarizable yes
Contains a Jacobian yes

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Invariants

Base field:  $\F_{23}$
Dimension:  $2$
L-polynomial:  $1 - 12 x + 70 x^{2} - 276 x^{3} + 529 x^{4}$
Frobenius angles:  $\pm0.0519709137119$, $\pm0.414830815663$
Angle rank:  $2$ (numerical)
Number field:  \(\Q(\sqrt{-8 -2 \sqrt{3}})\)
Galois group:  $D_{4}$
Jacobians:  $14$
Isomorphism classes:  22
Cyclic group of points:    no
Non-cyclic primes:   $2$

This isogeny class is simple and 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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $312$ $277056$ $147591288$ $77934744576$ $41372398716792$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $12$ $526$ $12132$ $278494$ $6427932$ $148021486$ $3404888436$ $78311140798$ $1801150592940$ $41426500509646$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 14 curves (of which all are hyperelliptic):

  • $y^2=5 x^6+20 x^5+12 x^4+x^3+3 x^2+11 x$
  • $y^2=11 x^6+22 x^5+16 x^4+x^3+4 x^2+10 x+22$
  • $y^2=10 x^6+13 x^5+18 x^4+5 x^3+12 x^2+10 x+11$
  • $y^2=21 x^6+11 x^5+7 x^4+16 x^2+21 x+22$
  • $y^2=7 x^6+8 x^5+13 x^4+15 x^3+14 x^2+22 x+10$
  • $y^2=12 x^6+22 x^5+19 x^4+12 x^3+21 x^2+2 x+5$
  • $y^2=10 x^6+11 x^5+14 x^4+19 x^3+9 x^2+13 x+21$
  • $y^2=3 x^6+14 x^5+22 x^4+5 x^3+21 x^2+17 x+20$
  • $y^2=22 x^6+18 x^5+11 x^4+2 x^3+5 x^2+20 x+14$
  • $y^2=20 x^6+19 x^5+2 x^4+4 x^3+14 x^2+16 x+22$
  • $y^2=7 x^6+22 x^5+21 x^3+12 x^2+11 x+20$
  • $y^2=21 x^6+18 x^5+19 x^4+12 x^3+7 x^2+13 x+10$
  • $y^2=13 x^5+x^4+18 x^3+6 x^2+22 x+19$
  • $y^2=17 x^6+17 x^5+19 x^4+22 x^3+7 x^2+15 x+18$

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{23}$.

Endomorphism algebra over $\F_{23}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-8 -2 \sqrt{3}})\).

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.23.m_cs$2$(not in LMFDB)