Properties

Label 2.13.a_ao
Base field $\F_{13}$
Dimension $2$
$p$-rank $2$
Ordinary yes
Supersingular no
Simple yes
Geometrically simple no
Primitive yes
Principally polarizable yes
Contains a Jacobian yes

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Invariants

Base field:  $\F_{13}$
Dimension:  $2$
L-polynomial:  $1 - 14 x^{2} + 169 x^{4}$
Frobenius angles:  $\pm0.159502860020$, $\pm0.840497139980$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{-3}, \sqrt{10})\)
Galois group:  $C_2^2$
Jacobians:  $10$
Isomorphism classes:  40
Cyclic group of points:    no
Non-cyclic primes:   $2$

This isogeny class is simple but not 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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $156$ $24336$ $4831164$ $823919616$ $137858273436$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $14$ $142$ $2198$ $28846$ $371294$ $4835518$ $62748518$ $815804638$ $10604499374$ $137858055022$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 10 curves (of which all are hyperelliptic):

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

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{13^{2}}$.

Endomorphism algebra over $\F_{13}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-3}, \sqrt{10})\).
Endomorphism algebra over $\overline{\F}_{13}$
The base change of $A$ to $\F_{13^{2}}$ is 1.169.ao 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-30}) \)$)$

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.13.ag_z$3$(not in LMFDB)
2.13.g_z$3$(not in LMFDB)
2.13.a_o$4$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.13.ag_z$3$(not in LMFDB)
2.13.g_z$3$(not in LMFDB)
2.13.a_o$4$(not in LMFDB)
2.13.g_z$6$(not in LMFDB)