Properties

Label 2.83.i_fu
Base field $\F_{83}$
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:  $\F_{83}$
Dimension:  $2$
L-polynomial:  $1 + 8 x + 150 x^{2} + 664 x^{3} + 6889 x^{4}$
Frobenius angles:  $\pm0.471015506635$, $\pm0.677803852112$
Angle rank:  $2$ (numerical)
Number field:  \(\Q(\sqrt{-7 +4 \sqrt{2}})\)
Galois group:  $D_{4}$
Jacobians:  $432$
Cyclic group of points:    no
Non-cyclic primes:   $2$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $7712$ $49110016$ $326314223648$ $2252083970686976$ $15515992695248572192$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $92$ $7126$ $570692$ $47453934$ $3939028332$ $326940232006$ $27136064431316$ $2252292184214238$ $186940253813368700$ $15516041198076523446$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 432 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{83}$.

Endomorphism algebra over $\F_{83}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-7 +4 \sqrt{2}})\).

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.83.ai_fu$2$(not in LMFDB)