Properties

Label 2.41.c_abu
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:  $1 + 2 x - 46 x^{2} + 82 x^{3} + 1681 x^{4}$
Frobenius angles:  $\pm0.200112285954$, $\pm0.915515338997$
Angle rank:  $2$ (numerical)
Number field:  \(\Q(\sqrt{-34 +2 \sqrt{129}})\)
Galois group:  $D_{4}$
Jacobians:  $28$
Cyclic group of points:    no
Non-cyclic primes:   $2$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $1720$ $2669440$ $4786830520$ $7987989544960$ $13425755563123000$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $44$ $1586$ $69452$ $2826846$ $115882924$ $4750218578$ $194754294604$ $7984926433726$ $327381878642732$ $13422659283168626$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 28 curves (of which all are hyperelliptic):

  • $y^2=21 x^6+8 x^5+24 x^4+19 x^3+3 x^2+30 x+24$
  • $y^2=23 x^6+13 x^5+24 x^4+3 x^3+12 x^2+38$
  • $y^2=11 x^6+23 x^5+6 x^4+2 x^3+32 x^2+20 x+24$
  • $y^2=20 x^6+6 x^5+4 x^4+12 x^3+5 x^2+24 x+13$
  • $y^2=5 x^6+17 x^5+37 x^4+3 x^3+14 x^2+35 x+32$
  • $y^2=9 x^6+6 x^5+24 x^4+21 x^3+32 x^2+20 x+20$
  • $y^2=18 x^6+17 x^5+16 x^4+13 x^3+5 x^2+20 x+2$
  • $y^2=x^6+38 x^5+6 x^4+24 x^3+25 x^2+37$
  • $y^2=12 x^6+31 x^5+18 x^4+27 x^3+34 x^2+15 x+2$
  • $y^2=20 x^6+33 x^5+40 x^4+36 x^3+12 x^2+29 x+20$
  • $y^2=35 x^5+20 x^4+25 x^3+40 x^2+8 x$
  • $y^2=15 x^6+36 x^5+9 x^4+39 x^3+13 x^2+11 x+20$
  • $y^2=32 x^6+3 x^5+22 x^4+24 x^3+30 x^2+22 x+28$
  • $y^2=14 x^6+24 x^5+19 x^4+33 x^3+23 x^2+9 x+19$
  • $y^2=15 x^6+36 x^5+12 x^4+25 x^3+14 x^2+39 x+25$
  • $y^2=4 x^6+29 x^5+27 x^4+34 x^3+28 x^2+17 x+25$
  • $y^2=21 x^6+2 x^5+5 x^4+37 x^3+16 x^2+21$
  • $y^2=10 x^6+4 x^5+25 x^4+32 x^3+4 x^2+22 x+28$
  • $y^2=20 x^6+7 x^5+35 x^4+19 x^3+16 x^2+27 x+12$
  • $y^2=10 x^6+22 x^5+5 x^4+8 x^3+23 x^2+5 x+30$
  • $y^2=31 x^6+32 x^5+5 x^4+31 x^3+22 x^2+31 x+8$
  • $y^2=38 x^6+26 x^5+40 x^4+14 x^3+22 x^2+14 x+29$
  • $y^2=13 x^6+10 x^5+25 x^4+2 x^3+16 x^2+20 x+8$
  • $y^2=39 x^6+3 x^5+18 x^4+15 x^3+23 x^2+30 x+5$
  • $y^2=13 x^6+2 x^5+4 x^4+36 x^3+20 x$
  • $y^2=34 x^6+9 x^5+22 x^4+25 x^3+31 x^2+17 x+13$
  • $y^2=30 x^6+6 x^5+29 x^4+39 x^3+2 x^2+17 x+28$
  • $y^2=25 x^6+38 x^5+35 x^4+7 x^3+21 x^2+14 x+11$

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 \(\Q(\sqrt{-34 +2 \sqrt{129}})\).

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.ac_abu$2$(not in LMFDB)