Properties

Label 2.89.a_fq
Base field $\F_{89}$
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:  $\F_{89}$
Dimension:  $2$
L-polynomial:  $1 + 146 x^{2} + 7921 x^{4}$
Frobenius angles:  $\pm0.403075820349$, $\pm0.596924179651$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\zeta_{8})\)
Galois group:  $C_2^2$
Jacobians:  $517$
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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $8068$ $65092624$ $496980933700$ $3935902059085824$ $31181719918850164228$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $90$ $8214$ $704970$ $62731294$ $5584059450$ $496980576438$ $44231334895530$ $3936588996741694$ $350356403707485210$ $31181719907734144854$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 517 curves (of which all are hyperelliptic):

  • $y^2=34 x^6+26 x^5+17 x^3+86 x^2+68 x+76$
  • $y^2=13 x^6+78 x^5+51 x^3+80 x^2+26 x+50$
  • $y^2=12 x^6+8 x^5+27 x^4+23 x^3+32 x^2+84 x+1$
  • $y^2=8 x^6+6 x^5+65 x^4+72 x^3+4 x^2+82 x+79$
  • $y^2=73 x^6+16 x^5+28 x^4+79 x^3+38 x^2+33 x+7$
  • $y^2=41 x^6+48 x^5+84 x^4+59 x^3+25 x^2+10 x+21$
  • $y^2=37 x^6+7 x^5+25 x^4+10 x^3+61 x^2+74 x+71$
  • $y^2=76 x^6+76 x^5+59 x^4+34 x^3+75 x^2+50 x+14$
  • $y^2=50 x^6+50 x^5+88 x^4+13 x^3+47 x^2+61 x+42$
  • $y^2=43 x^6+7 x^5+51 x^4+50 x^3+25 x^2+63 x+85$
  • $y^2=22 x^6+69 x^5+65 x^4+61 x^3+63 x^2+80 x+9$
  • $y^2=66 x^6+29 x^5+17 x^4+5 x^3+11 x^2+62 x+27$
  • $y^2=62 x^6+29 x^5+52 x^4+5 x^3+29 x^2+37 x+72$
  • $y^2=8 x^6+87 x^5+67 x^4+15 x^3+87 x^2+22 x+38$
  • $y^2=25 x^6+72 x^5+30 x^4+82 x^3+56 x^2+48 x+79$
  • $y^2=75 x^6+38 x^5+x^4+68 x^3+79 x^2+55 x+59$
  • $y^2=63 x^6+19 x^5+29 x^4+83 x^3+48 x^2+50 x+5$
  • $y^2=11 x^6+57 x^5+87 x^4+71 x^3+55 x^2+61 x+15$
  • $y^2=84 x^6+53 x^5+26 x^4+24 x^3+5 x^2+25 x+31$
  • $y^2=61 x^6+24 x^5+88 x^4+86 x^2+51 x+45$
  • and 497 more

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{89^{2}}$.

Endomorphism algebra over $\F_{89}$
The endomorphism algebra of this simple isogeny class is \(\Q(\zeta_{8})\).
Endomorphism algebra over $\overline{\F}_{89}$
The base change of $A$ to $\F_{89^{2}}$ is 1.7921.fq 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-2}) \)$)$

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.89.abk_ti$4$(not in LMFDB)
2.89.a_afq$4$(not in LMFDB)
2.89.bk_ti$4$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.89.abk_ti$4$(not in LMFDB)
2.89.a_afq$4$(not in LMFDB)
2.89.bk_ti$4$(not in LMFDB)
2.89.ai_bg$8$(not in LMFDB)
2.89.i_bg$8$(not in LMFDB)
2.89.as_jb$12$(not in LMFDB)
2.89.s_jb$12$(not in LMFDB)