Properties

Label 2.71.s_ip
Base field $\F_{71}$
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:  $\F_{71}$
Dimension:  $2$
L-polynomial:  $( 1 + 9 x + 71 x^{2} )^{2}$
  $1 + 18 x + 223 x^{2} + 1278 x^{3} + 5041 x^{4}$
Frobenius angles:  $\pm0.679331255589$, $\pm0.679331255589$
Angle rank:  $1$ (numerical)
Jacobians:  $42$
Cyclic group of points:    no
Non-cyclic primes:   $3$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $6561$ $26040609$ $127252012176$ $646076909949849$ $3255341340975115401$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $90$ $5164$ $355536$ $25424404$ $1804283550$ $128098892878$ $9095128829730$ $645753551967844$ $45848499916285296$ $3255243556758087004$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 42 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

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

Endomorphism algebra over $\F_{71}$
The isogeny class factors as 1.71.j 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-203}) \)$)$

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.as_ip$2$(not in LMFDB)
2.71.a_cj$2$(not in LMFDB)
2.71.aj_k$3$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.71.as_ip$2$(not in LMFDB)
2.71.a_cj$2$(not in LMFDB)
2.71.aj_k$3$(not in LMFDB)
2.71.a_acj$4$(not in LMFDB)
2.71.j_k$6$(not in LMFDB)