Properties

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

Related objects

Downloads

Learn more

Invariants

Base field:  $\F_{23}$
Dimension:  $2$
L-polynomial:  $( 1 + 4 x + 23 x^{2} )^{2}$
  $1 + 8 x + 62 x^{2} + 184 x^{3} + 529 x^{4}$
Frobenius angles:  $\pm0.636928592136$, $\pm0.636928592136$
Angle rank:  $1$ (numerical)
Jacobians:  $14$
Cyclic group of points:    no
Non-cyclic primes:   $2, 7$

This isogeny class is not 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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $784$ $313600$ $142945936$ $78400000000$ $41481173785744$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $32$ $590$ $11744$ $280158$ $6444832$ $147994670$ $3404795104$ $78312054718$ $1801149081632$ $41426500935950$

Jacobians and polarizations

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

Decomposition and endomorphism algebra

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

Endomorphism algebra over $\F_{23}$
The isogeny class factors as 1.23.e 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-19}) \)$)$

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.23.ai_ck$2$(not in LMFDB)
2.23.a_be$2$(not in LMFDB)
2.23.ae_ah$3$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.23.ai_ck$2$(not in LMFDB)
2.23.a_be$2$(not in LMFDB)
2.23.ae_ah$3$(not in LMFDB)
2.23.a_abe$4$(not in LMFDB)
2.23.e_ah$6$(not in LMFDB)