Properties

Label 2.71.a_fm
Base field $\F_{71}$
Dimension $2$
$p$-rank $0$
Ordinary no
Supersingular yes
Simple no
Geometrically simple no
Primitive yes
Principally polarizable yes
Contains a Jacobian yes

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Invariants

Base field:  $\F_{71}$
Dimension:  $2$
L-polynomial:  $( 1 + 71 x^{2} )^{2}$
  $1 + 142 x^{2} + 5041 x^{4}$
Frobenius angles:  $\pm0.5$, $\pm0.5$
Angle rank:  $0$ (numerical)
Jacobians:  $210$

This isogeny class is not simple, primitive, not ordinary, and supersingular. It is principally polarizable and contains a Jacobian.

Newton polygon

This isogeny class is supersingular.

$p$-rank:  $0$
Slopes:  $[1/2, 1/2, 1/2, 1/2]$

Point counts

Point counts of the abelian variety

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $5184$ $26873856$ $128100999744$ $645241282560000$ $3255243554618339904$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $72$ $5326$ $357912$ $25391518$ $1804229352$ $128101715566$ $9095120158392$ $645753429599038$ $45848500718449032$ $3255243558226798606$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 210 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{71^{2}}$.

Endomorphism algebra over $\F_{71}$
The isogeny class factors as 1.71.a 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-71}) \)$)$
Endomorphism algebra over $\overline{\F}_{71}$
The base change of $A$ to $\F_{71^{2}}$ is 1.5041.fm 2 and its endomorphism algebra is $\mathrm{M}_{2}(B)$, where $B$ is the quaternion algebra over \(\Q\) ramified at $71$ and $\infty$.

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.a_act$3$(not in LMFDB)
2.71.a_afm$4$(not in LMFDB)
2.71.a_a$8$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.71.a_act$3$(not in LMFDB)
2.71.a_afm$4$(not in LMFDB)
2.71.a_a$8$(not in LMFDB)
2.71.a_ct$12$(not in LMFDB)