Properties

Label 2.41.j_bo
Base field $\F_{41}$
Dimension $2$
$p$-rank $2$
Ordinary yes
Supersingular no
Simple yes
Geometrically simple no
Primitive yes
Principally polarizable yes
Contains a Jacobian yes

Related objects

Downloads

Learn more

Invariants

Base field:  $\F_{41}$
Dimension:  $2$
L-polynomial:  $1 + 9 x + 40 x^{2} + 369 x^{3} + 1681 x^{4}$
Frobenius angles:  $\pm0.414725704614$, $\pm0.918607628719$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{-3}, \sqrt{-83})\)
Galois group:  $C_2^2$
Jacobians:  $99$
Isomorphism classes:  81
Cyclic group of points:    no
Non-cyclic primes:   $2, 5$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $2100$ $2822400$ $4802490000$ $7975436313600$ $13420950417052500$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $51$ $1681$ $69678$ $2822401$ $115841451$ $4750094158$ $194754924051$ $7984930873921$ $327381886101438$ $13422659296032001$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 99 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{41^{3}}$.

Endomorphism algebra over $\F_{41}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-3}, \sqrt{-83})\).
Endomorphism algebra over $\overline{\F}_{41}$
The base change of $A$ to $\F_{41^{3}}$ is 1.68921.oo 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-83}) \)$)$

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.41.aj_bo$2$(not in LMFDB)
2.41.as_gh$3$(not in LMFDB)
2.41.aj_bo$6$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.41.aj_bo$2$(not in LMFDB)
2.41.as_gh$3$(not in LMFDB)
2.41.aj_bo$6$(not in LMFDB)
2.41.a_b$6$(not in LMFDB)
2.41.s_gh$6$(not in LMFDB)
2.41.a_ab$12$(not in LMFDB)