Properties

Label 2.41.k_dk
Base field $\F_{41}$
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:  $\F_{41}$
Dimension:  $2$
L-polynomial:  $1 + 10 x + 88 x^{2} + 410 x^{3} + 1681 x^{4}$
Frobenius angles:  $\pm0.515941759933$, $\pm0.760856164106$
Angle rank:  $2$ (numerical)
Number field:  \(\Q(\sqrt{-9 +2 \sqrt{19}})\)
Galois group:  $D_{4}$
Jacobians:  $74$
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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $2190$ $2956500$ $4722010110$ $7985021634000$ $13421240209584750$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $52$ $1758$ $68512$ $2825798$ $115843952$ $4750263918$ $194754429572$ $7984914582718$ $327381982282372$ $13422659435903598$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 74 curves (of which all are hyperelliptic):

  • $y^2=34 x^5+14 x^4+x^3+23 x^2+3 x+23$
  • $y^2=31 x^6+25 x^5+24 x^4+34 x^3+21 x^2+6$
  • $y^2=31 x^6+27 x^4+35 x^3+29 x^2+4 x$
  • $y^2=2 x^6+33 x^5+39 x^4+26 x^3+9 x^2+28 x+4$
  • $y^2=22 x^6+10 x^5+x^4+3 x^3+13 x^2+2 x+21$
  • $y^2=11 x^5+19 x^4+3 x^3+37 x^2+21 x+37$
  • $y^2=33 x^6+20 x^5+35 x^4+3 x^3+34 x^2+7$
  • $y^2=15 x^6+2 x^5+13 x^4+23 x^3+39 x^2+19 x+28$
  • $y^2=5 x^6+13 x^5+31 x^4+26 x^3+21 x^2+11 x+20$
  • $y^2=2 x^6+35 x^5+32 x^4+10 x^3+14 x^2+28 x+19$
  • $y^2=30 x^6+33 x^5+21 x^4+6 x^3+31 x^2+28 x+35$
  • $y^2=34 x^6+32 x^5+x^4+37 x^3+26 x^2+6 x+33$
  • $y^2=11 x^6+4 x^5+32 x^4+8 x^3+2 x^2+20 x+33$
  • $y^2=12 x^6+6 x^5+8 x^4+4 x^3+38 x^2+36 x+23$
  • $y^2=22 x^6+38 x^5+11 x^4+36 x^3+30 x^2+33 x+5$
  • $y^2=2 x^6+35 x^5+30 x^4+15 x^3+x^2+40 x+31$
  • $y^2=23 x^6+25 x^5+19 x^4+22 x^2+39 x+1$
  • $y^2=x^6+34 x^5+12 x^4+17 x^3+14 x^2+5 x+8$
  • $y^2=18 x^6+27 x^5+17 x^4+30 x^3+33 x^2+25 x+18$
  • $y^2=x^6+33 x^5+26 x^4+30 x^3+36 x^2+x+2$
  • and 54 more

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{41}$.

Endomorphism algebra over $\F_{41}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-9 +2 \sqrt{19}})\).

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.41.ak_dk$2$(not in LMFDB)