Properties

Label 2.83.k_by
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:  $1 + 10 x + 50 x^{2} + 830 x^{3} + 6889 x^{4}$
Frobenius angles:  $\pm0.376859941862$, $\pm0.876859941862$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(i, \sqrt{141})\)
Galois group:  $C_2^2$
Jacobians:  $176$
Cyclic group of points:    no
Non-cyclic primes:   $2$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $7780$ $47458000$ $328080211540$ $2252261764000000$ $15515403272687458900$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $94$ $6890$ $573778$ $47457678$ $3938878694$ $326940373370$ $27136045912538$ $2252292421764958$ $186940254740809294$ $15516041187205853450$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 176 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{83^{4}}$.

Endomorphism algebra over $\F_{83}$
The endomorphism algebra of this simple isogeny class is \(\Q(i, \sqrt{141})\).
Endomorphism algebra over $\overline{\F}_{83}$
The base change of $A$ to $\F_{83^{4}}$ is 1.47458321.amk 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-141}) \)$)$
Remainder of endomorphism lattice by field

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.ak_by$2$(not in LMFDB)
2.83.ak_by$4$(not in LMFDB)
2.83.a_aem$8$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.83.ak_by$2$(not in LMFDB)
2.83.ak_by$4$(not in LMFDB)
2.83.a_aem$8$(not in LMFDB)
2.83.a_em$8$(not in LMFDB)