Properties

Label 2.81.abg_py
Base field $\F_{3^{4}}$
Dimension $2$
$p$-rank $1$
Ordinary no
Supersingular no
Simple no
Geometrically simple no
Primitive yes
Principally polarizable yes
Contains a Jacobian yes

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Invariants

Base field:  $\F_{3^{4}}$
Dimension:  $2$
L-polynomial:  $( 1 - 9 x )^{2}( 1 - 14 x + 81 x^{2} )$
  $1 - 32 x + 414 x^{2} - 2592 x^{3} + 6561 x^{4}$
Frobenius angles:  $0$, $0$, $\pm0.216346895939$
Angle rank:  $1$ (numerical)
Jacobians:  $3$

This isogeny class is not simple, primitive, not ordinary, and not supersingular. It is principally polarizable and contains a Jacobian.

Newton polygon

$p$-rank:  $1$
Slopes:  $[0, 1/2, 1/2, 1]$

Point counts

Point counts of the abelian variety

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $4352$ $41779200$ $282004486400$ $1852970355916800$ $12157651951711430912$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $50$ $6366$ $530642$ $43045566$ $3486780530$ $282429103518$ $22876782455570$ $1853020045666686$ $150094633757983922$ $12157665446009349726$

Jacobians and polarizations

This isogeny class contains the Jacobians of 3 curves (of which all are hyperelliptic), and hence is principally polarizable:

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{3^{4}}$.

Endomorphism algebra over $\F_{3^{4}}$
The isogeny class factors as 1.81.as $\times$ 1.81.ao and its endomorphism algebra is a direct product of the endomorphism algebras for each isotypic factor. The endomorphism algebra for each factor is:

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.81.ae_adm$2$(not in LMFDB)
2.81.e_adm$2$(not in LMFDB)
2.81.bg_py$2$(not in LMFDB)
2.81.af_bk$3$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.81.ae_adm$2$(not in LMFDB)
2.81.e_adm$2$(not in LMFDB)
2.81.bg_py$2$(not in LMFDB)
2.81.af_bk$3$(not in LMFDB)
2.81.ao_gg$4$(not in LMFDB)
2.81.o_gg$4$(not in LMFDB)
2.81.ax_lc$6$(not in LMFDB)
2.81.f_bk$6$(not in LMFDB)
2.81.x_lc$6$(not in LMFDB)