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:  $210$
Cyclic group of points:    no
Non-cyclic primes:   $2, 3$

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):

  • $y^2=16 x^6+7 x^5+26 x^4+36 x^3+69 x^2+66 x+4$
  • $y^2=41 x^6+49 x^5+40 x^4+39 x^3+57 x^2+36 x+28$
  • $y^2=55 x^6+10 x^5+2 x^4+12 x^3+2 x^2+10 x+55$
  • $y^2=30 x^6+70 x^5+14 x^4+13 x^3+14 x^2+70 x+30$
  • $y^2=11 x^6+15 x^5+35 x^4+60 x^3+55 x^2+24 x+52$
  • $y^2=6 x^6+34 x^5+32 x^4+65 x^3+30 x^2+26 x+9$
  • $y^2=48 x^6+52 x^5+23 x^4+48 x^3+23 x^2+52 x+48$
  • $y^2=52 x^6+9 x^5+19 x^4+52 x^3+19 x^2+9 x+52$
  • $y^2=45 x^6+30 x^5+49 x^4+63 x^3+35 x^2+24 x+46$
  • $y^2=2 x^6+35 x^5+53 x^3+50 x^2+7 x+6$
  • $y^2=14 x^6+32 x^5+16 x^3+66 x^2+49 x+42$
  • $y^2=4 x^6+59 x^4+59 x^2+4$
  • $y^2=28 x^6+58 x^4+58 x^2+28$
  • $y^2=4 x^6+58 x^4+51 x^2+23$
  • $y^2=69 x^6+55 x^4+30 x^2+24$
  • $y^2=70 x^6+44 x^5+31 x^4+x^3+47 x^2+13 x+35$
  • $y^2=64 x^6+24 x^5+4 x^4+7 x^3+45 x^2+20 x+32$
  • $y^2=44 x^6+59 x^5+68 x^4+51 x^3+68 x^2+59 x+44$
  • $y^2=24 x^6+58 x^5+50 x^4+2 x^3+50 x^2+58 x+24$
  • $y^2=59 x^6+4 x^5+16 x^4+54 x^3+38 x^2+27 x+65$
  • and 190 more

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)