Properties

Label 2.83.a_acy
Base field $\F_{83}$
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:  $\F_{83}$
Dimension:  $2$
L-polynomial:  $1 - 76 x^{2} + 6889 x^{4}$
Frobenius angles:  $\pm0.174313180039$, $\pm0.825686819961$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{2}, \sqrt{-5})\)
Galois group:  $C_2^2$
Jacobians:  $195$
Isomorphism classes:  270

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $6814$ $46430596$ $326941505086$ $2253051914072976$ $15516041181756694414$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $84$ $6738$ $571788$ $47474326$ $3939040644$ $326942636802$ $27136050989628$ $2252292293908318$ $186940255267540404$ $15516041176307535378$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 195 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{83^{2}}$.

Endomorphism algebra over $\F_{83}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{2}, \sqrt{-5})\).
Endomorphism algebra over $\overline{\F}_{83}$
The base change of $A$ to $\F_{83^{2}}$ is 1.6889.acy 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-5}) \)$)$

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.83.a_cy$4$(not in LMFDB)
2.83.aw_ji$8$(not in LMFDB)
2.83.w_ji$8$(not in LMFDB)