Properties

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

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Invariants

Base field:  $\F_{23}$
Dimension:  $2$
L-polynomial:  $1 - 26 x^{2} + 529 x^{4}$
Frobenius angles:  $\pm0.154396142471$, $\pm0.845603857529$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{2}, \sqrt{-5})\)
Galois group:  $C_2^2$
Jacobians:  $55$
Cyclic group of points:    no
Non-cyclic primes:   $2, 3$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $504$ $254016$ $148059576$ $78525490176$ $41426509441464$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $24$ $478$ $12168$ $280606$ $6436344$ $148083262$ $3404825448$ $78311812798$ $1801152661464$ $41426507669278$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 55 curves (of which all are hyperelliptic):

  • $y^2=5 x^6+2 x^5+12 x^4+4 x^3+9 x^2+15 x+7$
  • $y^2=2 x^6+10 x^5+14 x^4+20 x^3+22 x^2+6 x+12$
  • $y^2=17 x^6+4 x^5+18 x^4+22 x^3+22 x^2+10 x+6$
  • $y^2=16 x^6+20 x^5+21 x^4+18 x^3+18 x^2+4 x+7$
  • $y^2=5 x^6+15 x^5+10 x^4+21 x^3+5 x^2+13$
  • $y^2=9 x^6+17 x^5+17 x^4+16 x^3+6 x^2+15 x+8$
  • $y^2=22 x^6+16 x^5+16 x^4+11 x^3+7 x^2+6 x+17$
  • $y^2=16 x^6+8 x^5+17 x^4+20 x^3+18 x^2+x+14$
  • $y^2=10 x^6+16 x^5+2 x^4+8 x^3+4 x^2+12 x+4$
  • $y^2=4 x^6+11 x^5+10 x^4+17 x^3+20 x^2+14 x+20$
  • $y^2=5 x^6+8 x^5+5 x^4+4 x^3+21 x^2+15 x+14$
  • $y^2=2 x^6+17 x^5+2 x^4+20 x^3+13 x^2+6 x+1$
  • $y^2=19 x^6+2 x^5+8 x^4+15 x^3+2 x^2+15 x+9$
  • $y^2=3 x^6+10 x^5+17 x^4+6 x^3+10 x^2+6 x+22$
  • $y^2=6 x^6+x^5+10 x^4+x^3+16 x^2+13 x+3$
  • $y^2=19 x^5+21 x^4+9 x^3+7 x^2+15 x+22$
  • $y^2=3 x^5+13 x^4+22 x^3+12 x^2+6 x+18$
  • $y^2=22 x^6+13 x^5+8 x^4+8 x^3+8 x^2+21 x+4$
  • $y^2=4 x^6+21 x^5+13 x^4+5 x^3+13 x^2+6 x+10$
  • $y^2=10 x^6+x^5+8 x^4+19 x^3+21 x^2+6 x+3$
  • and 35 more

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{23^{2}}$.

Endomorphism algebra over $\F_{23}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{2}, \sqrt{-5})\).
Endomorphism algebra over $\overline{\F}_{23}$
The base change of $A$ to $\F_{23^{2}}$ is 1.529.aba 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-10}) \)$)$

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.a_ba$4$(not in LMFDB)
2.23.am_cu$8$(not in LMFDB)
2.23.m_cu$8$(not in LMFDB)