Properties

Label 2.31.e_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:  $\pm0.458027021365$, $\pm0.663255536989$
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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $1144$ $1015872$ $881201464$ $852178449408$ $819607807488184$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $36$ $1054$ $29580$ $922750$ $28628436$ $887486110$ $27513022524$ $852891183358$ $26439602389764$ $819628324428574$

Jacobians and polarizations

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

  • $y^2=19 x^6+28 x^5+20 x^4+9 x^2+25 x+24$
  • $y^2=3 x^6+15 x^5+6 x^4+6 x^3+8 x^2+24 x+28$
  • $y^2=11 x^6+27 x^5+5 x^4+3 x^3+10 x^2+13 x+6$
  • $y^2=8 x^6+10 x^5+23 x^4+22 x^3+29 x^2+10 x+27$
  • $y^2=9 x^6+7 x^5+11 x^4+19 x^3+15 x^2+x$
  • $y^2=9 x^6+x^5+5 x^4+22 x^3+26 x^2+17 x+28$
  • $y^2=16 x^6+24 x^5+5 x^4+5 x^3+23 x^2+x+22$
  • $y^2=17 x^6+16 x^5+11 x^3+28 x^2+9 x+7$
  • $y^2=5 x^6+2 x^4+22 x^3+27 x^2+21 x+17$
  • $y^2=12 x^6+18 x^5+2 x^4+11 x^3+10 x^2+27 x+19$
  • $y^2=14 x^6+19 x^5+22 x^4+14 x^3+29 x^2+16 x+6$
  • $y^2=2 x^6+25 x^5+13 x^4+24 x^2+22$
  • $y^2=x^6+15 x^5+19 x^4+24 x^3+17 x^2+14$
  • $y^2=20 x^6+28 x^5+20 x^4+19 x^3+4 x^2+6 x+30$
  • $y^2=4 x^6+8 x^5+13 x^4+8 x^3+x^2+22 x+10$
  • $y^2=19 x^6+15 x^5+4 x^4+22 x^3+23 x^2+8 x+17$
  • $y^2=15 x^6+15 x^5+21 x^4+18 x^3+12 x^2+16 x+25$
  • $y^2=7 x^6+9 x^5+17 x^4+24 x^3+21 x^2+29 x+16$
  • $y^2=8 x^6+10 x^5+27 x^4+8 x^3+11 x^2+23 x+18$
  • $y^2=4 x^6+11 x^5+25 x^4+30 x^3+6 x^2+25 x+27$
  • 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.ae_cc$2$(not in LMFDB)