Properties

Label 2.71.a_cw
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:  $1 + 74 x^{2} + 5041 x^{4}$
Frobenius angles:  $\pm0.337244063214$, $\pm0.662755936786$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{-6}, \sqrt{17})\)
Galois group:  $C_2^2$
Jacobians:  $256$
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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $5116$ $26173456$ $128099570044$ $645987695698944$ $3255243552417538876$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $72$ $5190$ $357912$ $25420894$ $1804229352$ $128098856166$ $9095120158392$ $645753590462014$ $45848500718449032$ $3255243553825196550$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 256 curves (of which all are hyperelliptic):

  • $y^2=34 x^6+8 x^5+44 x^4+54 x^3+54 x^2+63 x+1$
  • $y^2=25 x^6+56 x^5+24 x^4+23 x^3+23 x^2+15 x+7$
  • $y^2=18 x^6+30 x^4+65 x^3+30 x^2+53 x+5$
  • $y^2=55 x^6+68 x^4+29 x^3+68 x^2+16 x+35$
  • $y^2=70 x^6+11 x^5+36 x^4+13 x^3+59 x^2+17 x+50$
  • $y^2=55 x^6+57 x^5+6 x^4+37 x^3+39 x^2+33 x+32$
  • $y^2=30 x^6+44 x^5+42 x^4+46 x^3+60 x^2+18 x+11$
  • $y^2=36 x^6+14 x^5+14 x^4+52 x^3+3 x^2+26 x+52$
  • $y^2=61 x^6+30 x^4+35 x^3+63 x^2+43$
  • $y^2=47 x^6+50 x^5+49 x^4+44 x^3+54 x^2+62 x+58$
  • $y^2=45 x^6+66 x^5+59 x^4+24 x^3+23 x^2+8 x+51$
  • $y^2=5 x^6+60 x^5+55 x^4+33 x^3+19 x^2+42 x+67$
  • $y^2=35 x^6+65 x^5+30 x^4+18 x^3+62 x^2+10 x+43$
  • $y^2=7 x^6+42 x^5+62 x^4+43 x^3+20 x^2+47 x+1$
  • $y^2=47 x^6+69 x^5+25 x^4+62 x^3+33 x^2+48 x+63$
  • $y^2=45 x^6+57 x^5+33 x^4+8 x^3+18 x^2+52 x+15$
  • $y^2=43 x^6+54 x^5+9 x^4+49 x^3+34 x^2+62 x+55$
  • $y^2=17 x^6+23 x^5+63 x^4+59 x^3+25 x^2+8 x+30$
  • $y^2=27 x^6+3 x^5+13 x^4+17 x^3+6 x^2+4 x+33$
  • $y^2=18 x^6+12 x^5+45 x^4+68 x^3+62 x^2+66 x+24$
  • and 236 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 \(\Q(\sqrt{-6}, \sqrt{17})\).
Endomorphism algebra over $\overline{\F}_{71}$
The base change of $A$ to $\F_{71^{2}}$ is 1.5041.cw 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-102}) \)$)$

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_acw$4$(not in LMFDB)