Properties

Label 2.41.a_abj
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:  $1 - 35 x^{2} + 1681 x^{4}$
Frobenius angles:  $\pm0.179815263399$, $\pm0.820184736601$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{13}, \sqrt{-47})\)
Galois group:  $C_2^2$
Jacobians:  $135$
Isomorphism classes:  250
Cyclic group of points:    no
Non-cyclic primes:   $3$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $1647$ $2712609$ $4750237872$ $7997012754201$ $13422659123486727$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $42$ $1612$ $68922$ $2830036$ $115856202$ $4750371502$ $194754273882$ $7984927398628$ $327381934393962$ $13422658936821052$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 135 curves (of which all are hyperelliptic):

  • $y^2=16 x^6+2 x^5+x^4+28 x^3+21 x^2+26 x+8$
  • $y^2=14 x^6+12 x^5+6 x^4+4 x^3+3 x^2+33 x+7$
  • $y^2=x^6+39 x^5+8 x^4+23 x^3+27 x^2+6$
  • $y^2=6 x^6+29 x^5+7 x^4+15 x^3+39 x^2+36$
  • $y^2=4 x^6+35 x^5+37 x^4+38 x^3+37 x^2+7 x+4$
  • $y^2=24 x^6+5 x^5+17 x^4+23 x^3+17 x^2+x+24$
  • $y^2=9 x^6+15 x^5+21 x^4+34 x^3+8 x^2+29 x+34$
  • $y^2=4 x^6+7 x^5+29 x^4+9 x^3+22 x^2+28 x+22$
  • $y^2=24 x^6+21 x^5+23 x^4+13 x^3+3 x^2+39 x+30$
  • $y^2=21 x^6+3 x^5+15 x^4+37 x^3+18 x^2+29 x+16$
  • $y^2=13 x^6+39 x^5+6 x^4+28 x^3+26 x^2+7 x+10$
  • $y^2=37 x^6+29 x^5+36 x^4+4 x^3+33 x^2+x+19$
  • $y^2=16 x^6+25 x^5+10 x^4+2 x^3+13 x^2+5 x+16$
  • $y^2=14 x^6+27 x^5+19 x^4+12 x^3+37 x^2+30 x+14$
  • $y^2=5 x^6+33 x^5+29 x^4+30 x^3+17 x^2+38 x+11$
  • $y^2=30 x^6+34 x^5+10 x^4+16 x^3+20 x^2+23 x+25$
  • $y^2=20 x^6+13 x^5+26 x^4+x^3+13 x^2+36 x+8$
  • $y^2=38 x^6+37 x^5+33 x^4+6 x^3+37 x^2+11 x+7$
  • $y^2=18 x^6+13 x^5+18 x^4+37 x^3+38 x^2+4 x+11$
  • $y^2=26 x^6+37 x^5+26 x^4+17 x^3+23 x^2+24 x+25$
  • and 115 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 \(\Q(\sqrt{13}, \sqrt{-47})\).
Endomorphism algebra over $\overline{\F}_{41}$
The base change of $A$ to $\F_{41^{2}}$ is 1.1681.abj 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-611}) \)$)$

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_bj$4$(not in LMFDB)