Properties

Label 2.71.ab_acs
Base field $\F_{71}$
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:  $\F_{71}$
Dimension:  $2$
L-polynomial:  $1 - x - 70 x^{2} - 71 x^{3} + 5041 x^{4}$
Frobenius angles:  $\pm0.147767347705$, $\pm0.814434014371$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{-3}, \sqrt{-283})\)
Galois group:  $C_2^2$
Jacobians:  $63$
Cyclic group of points:    no
Non-cyclic primes:   $2, 5, 7$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $4900$ $24715600$ $127949290000$ $646002610926400$ $3255198712919597500$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $71$ $4901$ $357488$ $25421481$ $1804204501$ $128101625678$ $9095122593691$ $645753576442801$ $45848501154655568$ $3255243548018994701$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 63 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{71^{3}}$.

Endomorphism algebra over $\F_{71}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-3}, \sqrt{-283})\).
Endomorphism algebra over $\overline{\F}_{71}$
The base change of $A$ to $\F_{71^{3}}$ is 1.357911.aie 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-283}) \)$)$

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.71.b_acs$2$(not in LMFDB)
2.71.c_fn$3$(not in LMFDB)
2.71.ac_fn$6$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.71.b_acs$2$(not in LMFDB)
2.71.c_fn$3$(not in LMFDB)
2.71.ac_fn$6$(not in LMFDB)
2.71.a_fl$6$(not in LMFDB)
2.71.a_afl$12$(not in LMFDB)