Properties

Label 2.11.b_ak
Base field $\F_{11}$
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:  $\F_{11}$
Dimension:  $2$
L-polynomial:  $1 + x - 10 x^{2} + 11 x^{3} + 121 x^{4}$
Frobenius angles:  $\pm0.214837341119$, $\pm0.881504007785$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{-3}, \sqrt{-43})\)
Galois group:  $C_2^2$
Jacobians:  $3$
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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $124$ $12400$ $1860496$ $217297600$ $26026306804$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $13$ $101$ $1396$ $14841$ $161603$ $1774838$ $19479473$ $214369201$ $2357757676$ $25937406101$

Jacobians and polarizations

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

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

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{11^{3}}$.

Endomorphism algebra over $\F_{11}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-3}, \sqrt{-43})\).
Endomorphism algebra over $\overline{\F}_{11}$
The base change of $A$ to $\F_{11^{3}}$ is 1.1331.bg 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-43}) \)$)$

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.11.ab_ak$2$2.121.av_mi
2.11.ac_x$3$(not in LMFDB)
2.11.a_v$6$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.11.ab_ak$2$2.121.av_mi
2.11.ac_x$3$(not in LMFDB)
2.11.a_v$6$(not in LMFDB)
2.11.c_x$6$(not in LMFDB)
2.11.a_av$12$(not in LMFDB)