Properties

Label 2.41.a_de
Base field $\F_{41}$
Dimension $2$
$p$-rank $0$
Ordinary no
Supersingular yes
Simple no
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:  $( 1 + 41 x^{2} )^{2}$
  $1 + 82 x^{2} + 1681 x^{4}$
Frobenius angles:  $\pm0.5$, $\pm0.5$
Angle rank:  $0$ (numerical)
Jacobians:  $68$
Cyclic group of points:    no
Non-cyclic primes:   $2, 3, 7$

This isogeny class is not simple, primitive, not ordinary, and supersingular. It is principally polarizable and contains a Jacobian.

Newton polygon

This isogeny class is supersingular.

$p$-rank:  $0$
Slopes:  $[1/2, 1/2, 1/2, 1/2]$

Point counts

Point counts of the abelian variety

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $1764$ $3111696$ $4750242084$ $7965941760000$ $13422659541864804$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $42$ $1846$ $68922$ $2819038$ $115856202$ $4750379926$ $194754273882$ $7984913926078$ $327381934393962$ $13422659773577206$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 68 curves (of which all are hyperelliptic):

  • $y^2=27 x^6+16 x^5+29 x^4+16 x^3+28 x^2+37 x+26$
  • $y^2=39 x^6+14 x^5+10 x^4+14 x^3+4 x^2+17 x+33$
  • $y^2=x^6+18 x^5+28 x^4+34 x^3+28 x^2+18 x+1$
  • $y^2=6 x^6+26 x^5+4 x^4+40 x^3+4 x^2+26 x+6$
  • $y^2=4 x^6+10 x^5+9 x^4+4 x^3+38 x^2+2 x+6$
  • $y^2=24 x^6+19 x^5+13 x^4+24 x^3+23 x^2+12 x+36$
  • $y^2=34 x^6+27 x^5+x^4+30 x^3+21 x^2+17 x+35$
  • $y^2=40 x^6+39 x^5+6 x^4+16 x^3+3 x^2+20 x+5$
  • $y^2=21 x^6+5 x^5+9 x^4+28 x^3+9 x^2+5 x+21$
  • $y^2=3 x^6+30 x^5+13 x^4+4 x^3+13 x^2+30 x+3$
  • $y^2=x^6+x^3+10$
  • $y^2=6 x^6+6 x^3+19$
  • $y^2=22 x^6+3 x^5+6 x^4+19 x^3+14 x^2+30 x+35$
  • $y^2=9 x^6+18 x^5+36 x^4+32 x^3+2 x^2+16 x+5$
  • $y^2=25 x^5+4 x^4+32 x^3+9 x^2+x$
  • $y^2=27 x^5+24 x^4+28 x^3+13 x^2+6 x$
  • $y^2=30 x^6+3 x^5+38 x^4+24 x^3+38 x^2+3 x+30$
  • $y^2=16 x^6+18 x^5+23 x^4+21 x^3+23 x^2+18 x+16$
  • $y^2=33 x^6+2 x^5+8 x^4+24 x^3+16 x^2+8 x+18$
  • $y^2=34 x^6+12 x^5+7 x^4+21 x^3+14 x^2+7 x+26$
  • and 48 more

Decomposition and endomorphism algebra

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

Endomorphism algebra over $\F_{41}$
The isogeny class factors as 1.41.a 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-41}) \)$)$
Endomorphism algebra over $\overline{\F}_{41}$
The base change of $A$ to $\F_{41^{2}}$ is 1.1681.de 2 and its endomorphism algebra is $\mathrm{M}_{2}(B)$, where $B$ is the quaternion algebra over \(\Q\) ramified at $41$ and $\infty$.

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.41.a_abp$3$(not in LMFDB)
2.41.a_ade$4$(not in LMFDB)
2.41.a_abp$6$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.41.a_abp$3$(not in LMFDB)
2.41.a_ade$4$(not in LMFDB)
2.41.a_abp$6$(not in LMFDB)
2.41.a_a$8$(not in LMFDB)
2.41.a_bp$12$(not in LMFDB)