Properties

Label 2.83.a_c
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:  $1 + 2 x^{2} + 6889 x^{4}$
Frobenius angles:  $\pm0.251917575829$, $\pm0.748082424171$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{41}, \sqrt{-42})\)
Galois group:  $C_2^2$
Jacobians:  $300$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $6892$ $47499664$ $326940332044$ $2253599898633216$ $15516041187680161132$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $84$ $6894$ $571788$ $47485870$ $3939040644$ $326940290718$ $27136050989628$ $2252292042526174$ $186940255267540404$ $15516041188154468814$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 300 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 \(\Q(\sqrt{41}, \sqrt{-42})\).
Endomorphism algebra over $\overline{\F}_{83}$
The base change of $A$ to $\F_{83^{2}}$ is 1.6889.c 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-1722}) \)$)$

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_ac$4$(not in LMFDB)