Properties

Label 2.31.ae_cc
Base field $\F_{31}$
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:  $\F_{31}$
Dimension:  $2$
L-polynomial:  $1 - 4 x + 54 x^{2} - 124 x^{3} + 961 x^{4}$
Frobenius angles:  $\pm0.336744463011$, $\pm0.541972978635$
Angle rank:  $2$ (numerical)
Number field:  \(\Q(\sqrt{-96 -46 \sqrt{3}})\)
Galois group:  $D_{4}$
Jacobians:  $56$
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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $888$ $1015872$ $893833272$ $852178449408$ $819648804433848$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $28$ $1054$ $30004$ $922750$ $28629868$ $887486110$ $27512205700$ $852891183358$ $26439641931580$ $819628324428574$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 56 curves (of which all are hyperelliptic):

  • $y^2=26 x^6+22 x^5+29 x^4+27 x^2+13 x+10$
  • $y^2=9 x^6+14 x^5+18 x^4+18 x^3+24 x^2+10 x+22$
  • $y^2=14 x^6+9 x^5+12 x^4+x^3+24 x^2+25 x+2$
  • $y^2=24 x^6+30 x^5+7 x^4+4 x^3+25 x^2+30 x+19$
  • $y^2=3 x^6+23 x^5+14 x^4+27 x^3+5 x^2+21 x$
  • $y^2=27 x^6+3 x^5+15 x^4+4 x^3+16 x^2+20 x+22$
  • $y^2=17 x^6+10 x^5+15 x^4+15 x^3+7 x^2+3 x+4$
  • $y^2=16 x^6+26 x^5+14 x^3+30 x^2+3 x+23$
  • $y^2=12 x^6+11 x^4+28 x^3+9 x^2+7 x+16$
  • $y^2=4 x^6+6 x^5+11 x^4+14 x^3+24 x^2+9 x+27$
  • $y^2=15 x^6+27 x^5+28 x^4+15 x^3+20 x^2+26 x+2$
  • $y^2=11 x^6+29 x^5+25 x^4+8 x^2+28$
  • $y^2=21 x^6+5 x^5+27 x^4+8 x^3+16 x^2+15$
  • $y^2=17 x^6+30 x^5+17 x^4+27 x^3+22 x^2+2 x+10$
  • $y^2=22 x^6+13 x^5+25 x^4+13 x^3+21 x^2+28 x+24$
  • $y^2=27 x^6+5 x^5+22 x^4+28 x^3+18 x^2+13 x+16$
  • $y^2=5 x^6+5 x^5+7 x^4+6 x^3+4 x^2+26 x+29$
  • $y^2=21 x^6+27 x^5+20 x^4+10 x^3+x^2+25 x+17$
  • $y^2=24 x^6+30 x^5+19 x^4+24 x^3+2 x^2+7 x+23$
  • $y^2=12 x^6+2 x^5+13 x^4+28 x^3+18 x^2+13 x+19$
  • and 36 more

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{31}$.

Endomorphism algebra over $\F_{31}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-96 -46 \sqrt{3}})\).

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.31.e_cc$2$(not in LMFDB)