Properties

Label 2.41.af_bc
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:  $1 - 5 x + 28 x^{2} - 205 x^{3} + 1681 x^{4}$
Frobenius angles:  $\pm0.204123793918$, $\pm0.634785462244$
Angle rank:  $2$ (numerical)
Number field:  \(\Q(\sqrt{-33 +2 \sqrt{241}})\)
Galois group:  $D_{4}$
Jacobians:  $120$
Isomorphism classes:  120
Cyclic group of points:    no
Non-cyclic primes:   $2, 5$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $1500$ $2880000$ $4728096000$ $7994062080000$ $13427279703037500$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $37$ $1713$ $68602$ $2828993$ $115896077$ $4750095438$ $194754313637$ $7984928417473$ $327381880387882$ $13422658973797473$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 120 curves (of which all are hyperelliptic):

  • $y^2=12 x^6+39 x^5+39 x^4+12 x^3+17 x^2+26$
  • $y^2=25 x^6+5 x^5+11 x^4+3 x^3+13 x^2+33 x+19$
  • $y^2=4 x^5+21 x^4+30 x^3+31 x^2+17 x+3$
  • $y^2=32 x^6+38 x^4+10 x^3+11 x^2+23 x+11$
  • $y^2=14 x^6+14 x^5+12 x^4+24 x^3+6 x^2+17 x+4$
  • $y^2=38 x^6+5 x^5+34 x^4+39 x^3+9 x^2+25 x+14$
  • $y^2=8 x^6+35 x^5+13 x^4+4 x^3+37 x^2+30 x+28$
  • $y^2=27 x^5+22 x^4+14 x^3+15 x^2+9 x+34$
  • $y^2=40 x^6+17 x^5+18 x^4+36 x^3+22 x^2+25 x+28$
  • $y^2=33 x^6+13 x^5+9 x^4+23 x^2+33 x+13$
  • $y^2=29 x^6+32 x^5+35 x^4+17 x^3+27 x^2+28 x+39$
  • $y^2=x^6+4 x^5+24 x^4+10 x^3+40 x^2+22 x+19$
  • $y^2=14 x^6+4 x^5+38 x^4+12 x^3+22 x^2+37 x+34$
  • $y^2=16 x^6+25 x^5+14 x^4+30 x^3+28 x^2+17 x+29$
  • $y^2=19 x^6+3 x^5+19 x^4+32 x^3+40 x^2+31 x+18$
  • $y^2=38 x^6+16 x^5+20 x^4+27 x^3+27 x^2+33 x+38$
  • $y^2=2 x^6+38 x^5+28 x^4+28 x^3+21 x^2+26 x+34$
  • $y^2=12 x^6+14 x^5+36 x^4+31 x^3+6 x^2+34 x$
  • $y^2=19 x^6+7 x^5+32 x^4+30 x^3+32 x^2+16 x+33$
  • $y^2=20 x^6+18 x^5+23 x^4+26 x^3+35 x^2+2 x+23$
  • and 100 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 \(\Q(\sqrt{-33 +2 \sqrt{241}})\).

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.f_bc$2$(not in LMFDB)