Properties

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

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Invariants

Base field:  $\F_{71}$
Dimension:  $2$
L-polynomial:  $1 + 4 x + 140 x^{2} + 284 x^{3} + 5041 x^{4}$
Frobenius angles:  $\pm0.491508933344$, $\pm0.585051347051$
Angle rank:  $2$ (numerical)
Number field:  \(\Q(\sqrt{-274 +4 \sqrt{6}})\)
Galois group:  $D_{4}$
Jacobians:  $40$
Isomorphism classes:  40
Cyclic group of points:    yes

This isogeny class is simple and 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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $5470$ $26770180$ $127827472750$ $645375606520720$ $3255372238539256750$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $76$ $5306$ $357148$ $25396806$ $1804300676$ $128100967418$ $9095115515156$ $645753508863166$ $45848500904375308$ $3255243551272915226$

Jacobians and polarizations

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

  • $y^2=49 x^6+2 x^5+46 x^4+7 x^3+6 x^2+40 x+30$
  • $y^2=12 x^6+58 x^5+66 x^4+18 x^3+51 x^2+52 x+26$
  • $y^2=15 x^6+11 x^5+40 x^4+19 x^3+70 x^2+52 x+5$
  • $y^2=23 x^6+15 x^5+67 x^4+64 x^3+50 x^2+20 x+3$
  • $y^2=26 x^6+49 x^5+12 x^4+47 x^3+7 x^2+20 x+43$
  • $y^2=29 x^6+31 x^5+66 x^4+69 x^3+19 x^2+46 x+64$
  • $y^2=4 x^6+57 x^5+60 x^4+70 x^3+12 x^2+65 x+61$
  • $y^2=13 x^6+20 x^5+50 x^4+52 x^3+17 x^2+52 x+61$
  • $y^2=57 x^6+66 x^5+54 x^4+12 x^3+50 x^2+64$
  • $y^2=36 x^6+16 x^5+21 x^4+40 x^3+61 x^2+41 x+42$
  • $y^2=47 x^6+2 x^5+14 x^4+36 x^3+60 x^2+39 x+69$
  • $y^2=52 x^6+14 x^5+52 x^4+67 x^3+28 x^2+69 x+68$
  • $y^2=33 x^6+11 x^5+65 x^4+3 x^3+21 x^2+68 x+31$
  • $y^2=50 x^6+52 x^5+51 x^4+23 x^3+41 x^2+49 x+44$
  • $y^2=37 x^6+52 x^5+26 x^4+x^3+55 x^2+31 x+62$
  • $y^2=6 x^6+3 x^5+19 x^4+10 x^3+65 x^2+45 x+45$
  • $y^2=11 x^6+8 x^5+4 x^4+25 x^3+39 x^2+7 x+57$
  • $y^2=20 x^6+56 x^5+53 x^4+44 x^3+37 x^2+10 x+45$
  • $y^2=6 x^6+62 x^5+34 x^4+8 x^3+53 x^2+64 x+22$
  • $y^2=57 x^6+49 x^5+64 x^4+34 x^3+45 x^2+14 x+2$
  • and 20 more

Decomposition and endomorphism algebra

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

Endomorphism algebra over $\F_{71}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-274 +4 \sqrt{6}})\).

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.ae_fk$2$(not in LMFDB)