Properties

Label 2.97.ab_bc
Base field $\F_{97}$
Dimension $2$
$p$-rank $2$
Ordinary yes
Supersingular no
Simple yes
Geometrically simple yes
Primitive yes
Principally polarizable yes
Contains a Jacobian yes

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Invariants

Base field:  $\F_{97}$
Dimension:  $2$
L-polynomial:  $1 - x + 28 x^{2} - 97 x^{3} + 9409 x^{4}$
Frobenius angles:  $\pm0.261994078676$, $\pm0.716617240495$
Angle rank:  $2$ (numerical)
Number field:  \(\Q(\sqrt{-886 +2 \sqrt{665}})\)
Galois group:  $D_{4}$
Jacobians:  $300$
Cyclic group of points:    no
Non-cyclic primes:   $2$

This isogeny class is simple and 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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $9340$ $89066240$ $832781448640$ $7840602642713600$ $73742896675593833500$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $97$ $9465$ $912466$ $88565073$ $8587396617$ $832970521470$ $80798286845401$ $7837433306990433$ $760231057626717202$ $73742412710699302825$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 300 curves (of which all are hyperelliptic):

  • $y^2=8 x^6+4 x^5+47 x^4+24 x^3+12 x^2+8 x+1$
  • $y^2=68 x^6+55 x^5+45 x^4+15 x^3+35 x^2+65 x+58$
  • $y^2=32 x^6+49 x^5+68 x^4+48 x^3+77 x^2+32 x+71$
  • $y^2=20 x^6+43 x^5+47 x^4+38 x^3+80 x^2+12 x+39$
  • $y^2=31 x^6+28 x^5+54 x^4+61 x^3+50 x^2+93 x+7$
  • $y^2=39 x^6+94 x^5+39 x^4+7 x^3+35 x^2+91 x+2$
  • $y^2=15 x^6+5 x^5+93 x^4+61 x^3+44 x^2+20 x+54$
  • $y^2=87 x^6+79 x^5+38 x^4+7 x^3+25 x^2+57 x+24$
  • $y^2=54 x^6+44 x^5+21 x^4+93 x^3+24 x^2+92 x+19$
  • $y^2=66 x^6+30 x^5+90 x^4+52 x^3+47 x^2+22 x+78$
  • $y^2=81 x^6+11 x^5+22 x^4+91 x^3+11 x^2+77 x+52$
  • $y^2=6 x^5+73 x^4+59 x^3+64 x^2+44 x+37$
  • $y^2=39 x^6+50 x^5+16 x^4+44 x^3+42 x^2+2 x+4$
  • $y^2=31 x^6+96 x^5+84 x^4+86 x^3+68 x^2+83 x+39$
  • $y^2=69 x^6+64 x^5+38 x^4+57 x^3+54 x^2+95 x+4$
  • $y^2=7 x^6+81 x^5+88 x^4+24 x^3+x^2+4 x+33$
  • $y^2=87 x^6+16 x^5+64 x^4+61 x^3+38 x^2+68 x+49$
  • $y^2=10 x^6+53 x^5+55 x^4+23 x^3+31 x^2+40 x+56$
  • $y^2=79 x^6+34 x^5+15 x^4+38 x^3+50 x^2+94 x+31$
  • $y^2=56 x^6+44 x^5+3 x^4+76 x^3+81 x^2+12 x+72$
  • and 280 more

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{97}$.

Endomorphism algebra over $\F_{97}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-886 +2 \sqrt{665}})\).

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.97.b_bc$2$(not in LMFDB)