Properties

Label 2.97.ab_ar
Base field $\F_{97}$
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:  $\F_{97}$
Dimension:  $2$
L-polynomial:  $1 - x - 17 x^{2} - 97 x^{3} + 9409 x^{4}$
Frobenius angles:  $\pm0.223598462506$, $\pm0.752432998049$
Angle rank:  $2$ (numerical)
Number field:  \(\Q(\sqrt{-706 +26 \sqrt{5}})\)
Galois group:  $D_{4}$
Jacobians:  $285$
Cyclic group of points:    no
Non-cyclic primes:   $13$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $9295$ $88218845$ $832659494095$ $7840674366335525$ $73742728559904118000$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $97$ $9375$ $912331$ $88565883$ $8587377042$ $832972959975$ $80798292836071$ $7837433278159923$ $760231058226972157$ $73742412675514246750$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 285 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

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

Endomorphism algebra over $\F_{97}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-706 +26 \sqrt{5}})\).

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.97.b_ar$2$(not in LMFDB)