Properties

Label 2.71.j_ge
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

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Invariants

Base field:  $\F_{71}$
Dimension:  $2$
L-polynomial:  $( 1 + 3 x + 71 x^{2} )( 1 + 6 x + 71 x^{2} )$
  $1 + 9 x + 160 x^{2} + 639 x^{3} + 5041 x^{4}$
Frobenius angles:  $\pm0.556968285566$, $\pm0.615871442562$
Angle rank:  $2$ (numerical)
Jacobians:  $40$
Cyclic group of points:    no
Non-cyclic primes:   $3, 5$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $5850$ $26640900$ $127502505000$ $645530959101600$ $3255511666751808750$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $81$ $5281$ $356238$ $25402921$ $1804377951$ $128100213178$ $9095111056161$ $645753573694321$ $45848501088886818$ $3255243547057117801$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 40 curves (of which all are hyperelliptic):

  • $y^2=67 x^6+42 x^5+56 x^4+43 x^3+4 x^2+11 x+21$
  • $y^2=38 x^6+57 x^5+40 x^4+7 x^3+67 x^2+13 x+36$
  • $y^2=38 x^6+19 x^5+21 x^4+17 x^3+20 x^2+61 x$
  • $y^2=3 x^6+60 x^5+39 x^4+30 x^3+51 x^2+34 x+10$
  • $y^2=9 x^6+8 x^5+27 x^4+30 x^3+28 x^2+62 x+32$
  • $y^2=43 x^6+58 x^5+26 x^4+60 x^3+70 x^2+2 x+67$
  • $y^2=13 x^6+5 x^5+14 x^4+54 x^3+47 x^2+58 x+39$
  • $y^2=7 x^6+17 x^5+53 x^4+23 x^3+56 x^2+63 x+52$
  • $y^2=68 x^6+57 x^5+4 x^4+11 x^3+48 x^2+24 x+60$
  • $y^2=44 x^6+38 x^5+62 x^4+67 x^3+61 x^2+35 x+15$
  • $y^2=14 x^6+61 x^5+56 x^4+42 x^3+45 x^2+3 x+7$
  • $y^2=69 x^6+60 x^5+65 x^4+34 x^3+62 x^2+38 x+50$
  • $y^2=7 x^6+46 x^5+24 x^4+46 x^3+27 x^2+14 x+31$
  • $y^2=12 x^6+41 x^5+22 x^4+21 x^3+43 x^2+43 x+32$
  • $y^2=9 x^6+8 x^5+3 x^4+53 x^3+60 x^2+64$
  • $y^2=63 x^6+12 x^5+11 x^4+52 x^3+47 x^2+70 x+45$
  • $y^2=40 x^6+22 x^5+43 x^4+70 x^3+48 x^2+25 x+41$
  • $y^2=29 x^6+10 x^5+61 x^4+9 x^3+24 x^2+58 x+23$
  • $y^2=12 x^6+29 x^5+47 x^4+63 x^3+41 x^2+15 x$
  • $y^2=31 x^6+54 x^5+38 x^4+54 x^3+59 x^2+29 x+19$
  • and 20 more

Decomposition and endomorphism algebra

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

Endomorphism algebra over $\F_{71}$
The isogeny class factors as 1.71.d $\times$ 1.71.g and its endomorphism algebra is a direct product of the endomorphism algebras for each isotypic factor. The endomorphism algebra for each factor is:

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.aj_ge$2$(not in LMFDB)
2.71.ad_eu$2$(not in LMFDB)
2.71.d_eu$2$(not in LMFDB)