Properties

Label 2.97.a_hm
Base field $\F_{97}$
Dimension $2$
$p$-rank $0$
Ordinary no
Supersingular yes
Simple no
Geometrically simple no
Primitive yes
Principally polarizable yes
Contains a Jacobian yes

Related objects

Downloads

Learn more

Invariants

Base field:  $\F_{97}$
Dimension:  $2$
L-polynomial:  $( 1 + 97 x^{2} )^{2}$
  $1 + 194 x^{2} + 9409 x^{4}$
Frobenius angles:  $\pm0.5$, $\pm0.5$
Angle rank:  $0$ (numerical)
Jacobians:  $63$

This isogeny class is not simple, primitive, not ordinary, and supersingular. It is principally polarizable and contains a Jacobian.

Newton polygon

This isogeny class is supersingular.

$p$-rank:  $0$
Slopes:  $[1/2, 1/2, 1/2, 1/2]$

Point counts

Point counts of the abelian variety

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $9604$ $92236816$ $832973830276$ $7834102237495296$ $73742412706667506564$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $98$ $9798$ $912674$ $88491646$ $8587340258$ $832975655622$ $80798284478114$ $7837433240259838$ $760231058654565218$ $73742412723842187078$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 63 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{97^{2}}$.

Endomorphism algebra over $\F_{97}$
The isogeny class factors as 1.97.a 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-97}) \)$)$
Endomorphism algebra over $\overline{\F}_{97}$
The base change of $A$ to $\F_{97^{2}}$ is 1.9409.hm 2 and its endomorphism algebra is $\mathrm{M}_{2}(B)$, where $B$ is the quaternion algebra over \(\Q\) ramified at $97$ and $\infty$.

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.97.a_adt$3$(not in LMFDB)
2.97.a_ahm$4$(not in LMFDB)
2.97.a_adt$6$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.97.a_adt$3$(not in LMFDB)
2.97.a_ahm$4$(not in LMFDB)
2.97.a_adt$6$(not in LMFDB)
2.97.a_a$8$(not in LMFDB)
2.97.a_dt$12$(not in LMFDB)