Properties

Label 2.23.c_ai
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:  $1 + 2 x - 8 x^{2} + 46 x^{3} + 529 x^{4}$
Frobenius angles:  $\pm0.266750468722$, $\pm0.840756633373$
Angle rank:  $2$ (numerical)
Number field:  \(\Q(\sqrt{-36 +2 \sqrt{55}})\)
Galois group:  $D_{4}$
Jacobians:  $28$
Isomorphism classes:  56
Cyclic group of points:    yes

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $570$ $270180$ $150423570$ $78725048400$ $41416614689250$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $26$ $510$ $12362$ $281318$ $6434806$ $148052430$ $3404609542$ $78310839358$ $1801151278826$ $41426513993550$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 28 curves (of which all are hyperelliptic):

  • $y^2=6 x^6+22 x^5+2 x^4+13 x^3+9 x^2+10 x+19$
  • $y^2=9 x^6+x^5+9 x^4+11 x^3+20 x^2+2 x+20$
  • $y^2=3 x^6+22 x^5+17 x^4+3 x^3+13 x^2+9 x$
  • $y^2=20 x^5+11 x^4+3 x^3+8 x^2+15 x+2$
  • $y^2=4 x^6+12 x^5+21 x^4+2 x^3+5 x^2+22 x+15$
  • $y^2=10 x^6+8 x^5+18 x^4+15 x^3+20 x^2+14 x+12$
  • $y^2=3 x^6+3 x^5+8 x^4+17 x^3+17 x^2+5 x+17$
  • $y^2=5 x^6+7 x^5+10 x^4+2 x^3+12 x^2+22 x+2$
  • $y^2=4 x^6+17 x^5+6 x^4+20 x^3+19 x^2+12 x+8$
  • $y^2=6 x^6+4 x^5+17 x^4+18 x^3+16 x^2+19 x+13$
  • $y^2=18 x^6+20 x^5+18 x^4+5 x^3+6 x^2+13 x+1$
  • $y^2=11 x^6+22 x^5+4 x^4+12 x^3+22 x^2+2 x+20$
  • $y^2=16 x^6+9 x^5+15 x^4+4 x^3+21 x^2+21 x+21$
  • $y^2=16 x^6+15 x^5+14 x^4+14 x^3+16 x^2+8 x+18$
  • $y^2=19 x^6+20 x^5+20 x^4+17 x^3+13 x^2+6 x+21$
  • $y^2=3 x^6+6 x^5+20 x^4+4 x^3+18 x^2+7 x+2$
  • $y^2=11 x^6+21 x^5+13 x^4+11 x^3+12 x^2+4 x+18$
  • $y^2=9 x^5+14 x^3+6 x^2+5 x+8$
  • $y^2=11 x^6+10 x^5+11 x^4+7 x^2+18 x+5$
  • $y^2=9 x^6+11 x^5+17 x^4+19 x^2+22 x+15$
  • $y^2=14 x^6+5 x^5+11 x^4+10 x^3+21 x^2+4 x+22$
  • $y^2=8 x^6+13 x^5+12 x^4+3 x^3+20 x^2+7 x+20$
  • $y^2=2 x^6+3 x^5+15 x^4+2 x^3+19 x^2+7 x+3$
  • $y^2=15 x^6+18 x^5+17 x^4+9 x^3+21 x^2+22 x+11$
  • $y^2=2 x^6+2 x^5+11 x^4+10 x^3+6 x^2+8 x+19$
  • $y^2=12 x^6+7 x^5+15 x^4+x^3+5 x^2+20 x+17$
  • $y^2=19 x^6+9 x^5+15 x^4+3 x^3+9 x^2+8 x+15$
  • $y^2=10 x^6+17 x^5+4 x^4+13 x^3+15 x^2+16 x+7$

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 \(\Q(\sqrt{-36 +2 \sqrt{55}})\).

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.ac_ai$2$(not in LMFDB)