Properties

Label 2.191.abw_bkn
Base field $\F_{191}$
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:  $\F_{191}$
Dimension:  $2$
L-polynomial:  $( 1 - 27 x + 191 x^{2} )( 1 - 21 x + 191 x^{2} )$
  $1 - 48 x + 949 x^{2} - 9168 x^{3} + 36481 x^{4}$
Frobenius angles:  $\pm0.0686610702072$, $\pm0.225319681555$
Angle rank:  $2$ (numerical)
Jacobians:  $56$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $28215$ $1316145105$ $48541194797040$ $1771226609260596345$ $64615163346536461275375$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $144$ $36076$ $6966432$ $1330885396$ $254195355024$ $48551228719198$ $9273284160084144$ $1771197283896842596$ $338298681536249667552$ $64615048177803910314076$

Jacobians and polarizations

This isogeny class contains the Jacobians of 56 curves (of which all are hyperelliptic), and hence is principally polarizable:

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{191}$.

Endomorphism algebra over $\F_{191}$
The isogeny class factors as 1.191.abb $\times$ 1.191.av and its endomorphism algebra is a direct product of the endomorphism algebras for each isotypic factor. The endomorphism algebra for each factor is:

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.191.ag_ahd$2$(not in LMFDB)
2.191.g_ahd$2$(not in LMFDB)
2.191.bw_bkn$2$(not in LMFDB)