Properties

Label 2.41.a_n
Base field $\F_{41}$
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:  $\F_{41}$
Dimension:  $2$
L-polynomial:  $1 + 13 x^{2} + 1681 x^{4}$
Frobenius angles:  $\pm0.275338790576$, $\pm0.724661209424$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{69}, \sqrt{-95})\)
Galois group:  $C_2^2$
Jacobians:  $180$
Cyclic group of points:    yes

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $1695$ $2873025$ $4750040880$ $8002986392025$ $13422659475732375$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $42$ $1708$ $68922$ $2832148$ $115856202$ $4749977518$ $194754273882$ $7984916141668$ $327381934393962$ $13422659641312348$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 180 curves (of which all are hyperelliptic):

  • $y^2=34 x^6+31 x^5+22 x^4+38 x^3+20 x^2+17 x+31$
  • $y^2=40 x^6+22 x^5+9 x^4+23 x^3+38 x^2+20 x+22$
  • $y^2=40 x^6+x^5+17 x^4+21 x^3+3 x^2+23 x+21$
  • $y^2=39 x^6+12 x^5+26 x^4+21 x^3+13 x^2+36 x+14$
  • $y^2=29 x^6+31 x^5+33 x^4+3 x^3+37 x^2+11 x+2$
  • $y^2=17 x^6+25 x^5+31 x^4+37 x^3+40 x^2+x+35$
  • $y^2=20 x^6+27 x^5+22 x^4+17 x^3+35 x^2+6 x+5$
  • $y^2=31 x^6+26 x^5+8 x^4+2 x^3+24 x^2+9 x+31$
  • $y^2=22 x^6+33 x^5+7 x^4+12 x^3+21 x^2+13 x+22$
  • $y^2=35 x^6+34 x^5+14 x^4+33 x^3+34 x^2+10 x+40$
  • $y^2=5 x^6+40 x^5+2 x^4+34 x^3+40 x^2+19 x+35$
  • $y^2=15 x^6+x^5+35 x^4+9 x^3+35 x^2+4 x+14$
  • $y^2=8 x^6+6 x^5+5 x^4+13 x^3+5 x^2+24 x+2$
  • $y^2=2 x^6+32 x^5+32 x^4+26 x^3+29 x^2+22 x+7$
  • $y^2=12 x^6+28 x^5+28 x^4+33 x^3+10 x^2+9 x+1$
  • $y^2=5 x^6+4 x^5+5 x^4+32 x^3+31 x^2+x+35$
  • $y^2=2 x^6+23 x^4+9 x^3+5 x^2+4 x+14$
  • $y^2=12 x^6+15 x^4+13 x^3+30 x^2+24 x+2$
  • $y^2=33 x^6+x^5+38 x^4+13 x^3+23 x^2+8 x+31$
  • $y^2=34 x^6+6 x^5+23 x^4+37 x^3+15 x^2+7 x+22$
  • and 160 more

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{41^{2}}$.

Endomorphism algebra over $\F_{41}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{69}, \sqrt{-95})\).
Endomorphism algebra over $\overline{\F}_{41}$
The base change of $A$ to $\F_{41^{2}}$ is 1.1681.n 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-6555}) \)$)$

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.a_an$4$(not in LMFDB)