Properties

Label 2.13.ac_d
Base field $\F_{13}$
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:  $\F_{13}$
Dimension:  $2$
L-polynomial:  $1 - 2 x + 3 x^{2} - 26 x^{3} + 169 x^{4}$
Frobenius angles:  $\pm0.195060026239$, $\pm0.681837234905$
Angle rank:  $2$ (numerical)
Number field:  \(\Q(\sqrt{-27 +4 \sqrt{6}})\)
Galois group:  $D_{4}$
Jacobians:  $12$
Cyclic group of points:    yes

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $145$ $29145$ $4679440$ $829612425$ $138438127225$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $12$ $172$ $2130$ $29044$ $372852$ $4826374$ $62766996$ $815728036$ $10604163930$ $137858383132$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 12 curves (of which all are hyperelliptic):

  • $y^2=6 x^6+6 x^5+4 x^4+12 x^3+11 x^2+11 x+7$
  • $y^2=9 x^6+x^5+10 x^4+5 x^3+9 x^2+4 x+4$
  • $y^2=10 x^6+8 x^5+9 x^4+5 x^3+9 x^2+4 x+8$
  • $y^2=2 x^6+5 x^5+2 x^4+2 x^3+10 x^2+9$
  • $y^2=11 x^6+10 x^5+x^4+3 x^3+2 x^2+x+4$
  • $y^2=6 x^6+12 x^4+6 x^3+7 x^2+11 x+4$
  • $y^2=11 x^6+8 x^5+9 x^4+11 x^3+6 x^2+12 x+9$
  • $y^2=9 x^6+3 x^5+5 x^4+4 x^3+12 x^2+12 x+8$
  • $y^2=x^6+5 x^5+6 x^4+9 x^3+10 x^2+10 x+8$
  • $y^2=12 x^6+8 x^5+4 x^4+2 x^3+12 x^2+5 x+6$
  • $y^2=7 x^6+5 x^5+12 x^4+5 x^3+8 x^2+8 x+10$
  • $y^2=2 x^6+7 x^5+7 x^4+3 x^3+6 x^2+12 x+4$

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{13}$.

Endomorphism algebra over $\F_{13}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-27 +4 \sqrt{6}})\).

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.13.c_d$2$2.169.c_jj