Properties

Label 2.43.a_bk
Base field $\F_{43}$
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:  $\F_{43}$
Dimension:  $2$
L-polynomial:  $1 + 36 x^{2} + 1849 x^{4}$
Frobenius angles:  $\pm0.318740346075$, $\pm0.681259653925$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{2}, \sqrt{-61})\)
Galois group:  $C_2^2$
Jacobians:  $135$
Cyclic group of points:    yes

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $1886$ $3556996$ $6321210014$ $11704636809616$ $21611482557799886$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $44$ $1922$ $79508$ $3423606$ $147008444$ $6321056978$ $271818611108$ $11688202413598$ $502592611936844$ $21611482802315522$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 135 curves (of which all are hyperelliptic):

  • $y^2=2 x^6+7 x^5+20 x^4+14 x^3+2 x^2+3 x$
  • $y^2=6 x^6+21 x^5+17 x^4+42 x^3+6 x^2+9 x$
  • $y^2=21 x^6+27 x^5+41 x^4+25 x^3+32 x^2+26 x+9$
  • $y^2=20 x^6+38 x^5+37 x^4+32 x^3+10 x^2+35 x+27$
  • $y^2=29 x^6+6 x^5+11 x^4+41 x^3+36 x^2+39 x+41$
  • $y^2=x^6+18 x^5+33 x^4+37 x^3+22 x^2+31 x+37$
  • $y^2=36 x^6+26 x^5+22 x^4+14 x^3+40 x^2+24 x+40$
  • $y^2=22 x^6+35 x^5+23 x^4+42 x^3+34 x^2+29 x+34$
  • $y^2=4 x^6+7 x^5+15 x^4+18 x^3+36 x+21$
  • $y^2=12 x^6+21 x^5+2 x^4+11 x^3+22 x+20$
  • $y^2=17 x^6+38 x^5+7 x^4+22 x^3+28 x^2+10 x+20$
  • $y^2=8 x^6+28 x^5+21 x^4+23 x^3+41 x^2+30 x+17$
  • $y^2=32 x^6+7 x^5+16 x^4+18 x^3+40 x^2+11 x+11$
  • $y^2=10 x^6+21 x^5+5 x^4+11 x^3+34 x^2+33 x+33$
  • $y^2=4 x^6+23 x^5+2 x^4+40 x^3+37 x^2+42 x+33$
  • $y^2=12 x^6+26 x^5+6 x^4+34 x^3+25 x^2+40 x+13$
  • $y^2=40 x^6+33 x^5+28 x^4+13 x^3+23 x^2+41 x+17$
  • $y^2=34 x^6+13 x^5+41 x^4+39 x^3+26 x^2+37 x+8$
  • $y^2=4 x^6+8 x^5+7 x^4+21 x^2+14 x+22$
  • $y^2=40 x^6+40 x^5+30 x^4+40 x^3+28 x^2+21 x+10$
  • and 115 more

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{43^{2}}$.

Endomorphism algebra over $\F_{43}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{2}, \sqrt{-61})\).
Endomorphism algebra over $\overline{\F}_{43}$
The base change of $A$ to $\F_{43^{2}}$ is 1.1849.bk 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-61}) \)$)$

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.43.a_abk$4$(not in LMFDB)
2.43.ak_by$8$(not in LMFDB)
2.43.k_by$8$(not in LMFDB)