Properties

Label 2.81.abi_rj
Base field $\F_{3^{4}}$
Dimension $2$
$p$-rank $2$
Ordinary yes
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:  $( 1 - 17 x + 81 x^{2} )^{2}$
  $1 - 34 x + 451 x^{2} - 2754 x^{3} + 6561 x^{4}$
Frobenius angles:  $\pm0.106600758076$, $\pm0.106600758076$
Angle rank:  $1$ (numerical)
Jacobians:  $5$

This isogeny class is not 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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $4225$ $41409225$ $281600035600$ $1852761401001225$ $12157750704111390625$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $48$ $6308$ $529878$ $43040708$ $3486808848$ $282430439198$ $22876805821008$ $1853020342954628$ $150094636834096758$ $12157665472705262948$

Jacobians and polarizations

This isogeny class contains the Jacobians of 5 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.ar 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-35}) \)$)$

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.a_aex$2$(not in LMFDB)
2.81.bi_rj$2$(not in LMFDB)
2.81.r_ia$3$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.81.a_aex$2$(not in LMFDB)
2.81.bi_rj$2$(not in LMFDB)
2.81.r_ia$3$(not in LMFDB)
2.81.a_ex$4$(not in LMFDB)
2.81.ar_ia$6$(not in LMFDB)