Properties

Label 2.83.a_fa
Base field $\F_{83}$
Dimension $2$
$p$-rank $2$
Ordinary yes
Supersingular no
Simple no
Geometrically simple no
Primitive yes
Principally polarizable yes
Contains a Jacobian yes

Related objects

Downloads

Learn more

Invariants

Base field:  $\F_{83}$
Dimension:  $2$
L-polynomial:  $( 1 - 6 x + 83 x^{2} )( 1 + 6 x + 83 x^{2} )$
  $1 + 130 x^{2} + 6889 x^{4}$
Frobenius angles:  $\pm0.393189690303$, $\pm0.606810309697$
Angle rank:  $1$ (numerical)
Jacobians:  $1050$
Cyclic group of points:    no
Non-cyclic primes:   $2, 3$

This isogeny class is not 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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $7020$ $49280400$ $326939883660$ $2251996007040000$ $15516041179507397100$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $84$ $7150$ $571788$ $47452078$ $3939040644$ $326939393950$ $27136050989628$ $2252292402478558$ $186940255267540404$ $15516041171808940750$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 1050 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 isogeny class factors as 1.83.ag $\times$ 1.83.g and its endomorphism algebra is a direct product of the endomorphism algebras for each isotypic factor. The endomorphism algebra for each factor is:
Endomorphism algebra over $\overline{\F}_{83}$
The base change of $A$ to $\F_{83^{2}}$ is 1.6889.fa 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-74}) \)$)$

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.am_hu$2$(not in LMFDB)
2.83.m_hu$2$(not in LMFDB)
2.83.a_afa$4$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.83.am_hu$2$(not in LMFDB)
2.83.m_hu$2$(not in LMFDB)
2.83.a_afa$4$(not in LMFDB)
2.83.ag_abv$6$(not in LMFDB)
2.83.g_abv$6$(not in LMFDB)