Properties

Label 2.71.a_eo
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

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Invariants

Base field:  $\F_{71}$
Dimension:  $2$
L-polynomial:  $1 + 118 x^{2} + 5041 x^{4}$
Frobenius angles:  $\pm0.406111524872$, $\pm0.593888475128$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{6}, \sqrt{-65})\)
Galois group:  $C_2^2$
Jacobians:  $424$
Cyclic group of points:    no
Non-cyclic primes:   $2$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $5160$ $26625600$ $128100142440$ $645558333465600$ $3255243547467729000$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $72$ $5278$ $357912$ $25403998$ $1804229352$ $128100000958$ $9095120158392$ $645753603370558$ $45848500718449032$ $3255243543925576798$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 424 curves (of which all are hyperelliptic):

  • $y^2=62 x^6+12 x^5+49 x^4+30 x^3+10 x^2+69 x+66$
  • $y^2=8 x^6+13 x^5+59 x^4+68 x^3+70 x^2+57 x+36$
  • $y^2=48 x^6+67 x^5+2 x^4+6 x^3+23 x^2+68 x+53$
  • $y^2=52 x^6+43 x^5+14 x^4+42 x^3+19 x^2+50 x+16$
  • $y^2=34 x^5+10 x^4+5 x^2+34 x+29$
  • $y^2=25 x^5+70 x^4+35 x^2+25 x+61$
  • $y^2=34 x^6+46 x^5+35 x^4+60 x^3+67 x^2+37 x+46$
  • $y^2=25 x^6+38 x^5+32 x^4+65 x^3+43 x^2+46 x+38$
  • $y^2=35 x^6+26 x^5+30 x^4+69 x^3+21 x+58$
  • $y^2=32 x^6+40 x^5+68 x^4+57 x^3+5 x+51$
  • $y^2=44 x^6+6 x^5+18 x^4+46 x^3+19 x^2+15 x+52$
  • $y^2=46 x^6+46 x^5+67 x^4+17 x^3+30 x^2+43 x+10$
  • $y^2=38 x^6+38 x^5+43 x^4+48 x^3+68 x^2+17 x+70$
  • $y^2=49 x^6+34 x^5+9 x^4+3 x^3+33 x^2+4 x+49$
  • $y^2=25 x^6+55 x^5+41 x^4+60 x^3+50 x^2+25 x+11$
  • $y^2=33 x^6+30 x^5+3 x^4+65 x^3+66 x^2+33 x+6$
  • $y^2=46 x^6+6 x^5+46 x^4+31 x^3+51 x^2+62 x+33$
  • $y^2=38 x^6+42 x^5+38 x^4+4 x^3+2 x^2+8 x+18$
  • $y^2=15 x^6+19 x^5+18 x^4+14 x^3+12 x^2+32 x+30$
  • $y^2=34 x^6+62 x^5+55 x^4+27 x^3+13 x^2+11 x+68$
  • and 404 more

Decomposition and endomorphism algebra

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

Endomorphism algebra over $\F_{71}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{6}, \sqrt{-65})\).
Endomorphism algebra over $\overline{\F}_{71}$
The base change of $A$ to $\F_{71^{2}}$ is 1.5041.eo 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-390}) \)$)$

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.71.a_aeo$4$(not in LMFDB)