Properties

Label 2.83.a_abt
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:  $1 - 45 x^{2} + 6889 x^{4}$
Frobenius angles:  $\pm0.206308884932$, $\pm0.793691115068$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(i, \sqrt{211})\)
Galois group:  $C_2^2$
Jacobians:  $165$
Isomorphism classes:  93
Cyclic group of points:    yes

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $6845$ $46854025$ $326941212260$ $2253408020505625$ $15516041179482003725$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $84$ $6800$ $571788$ $47481828$ $3939040644$ $326942051150$ $27136050989628$ $2252292145706308$ $186940255267540404$ $15516041171758154000$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 165 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 \(\Q(i, \sqrt{211})\).
Endomorphism algebra over $\overline{\F}_{83}$
The base change of $A$ to $\F_{83^{2}}$ is 1.6889.abt 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-211}) \)$)$

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.83.aw_lb$4$(not in LMFDB)
2.83.a_bt$4$(not in LMFDB)
2.83.w_lb$4$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.83.aw_lb$4$(not in LMFDB)
2.83.a_bt$4$(not in LMFDB)
2.83.w_lb$4$(not in LMFDB)
2.83.al_bm$12$(not in LMFDB)
2.83.l_bm$12$(not in LMFDB)