Properties

Label 2.83.a_acs
Base field $\F_{83}$
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:  $\F_{83}$
Dimension:  $2$
L-polynomial:  $1 - 70 x^{2} + 6889 x^{4}$
Frobenius angles:  $\pm0.180719097892$, $\pm0.819280902108$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{-6}, \sqrt{59})\)
Galois group:  $C_2^2$
Jacobians:  $440$
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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $6820$ $46512400$ $326941477060$ $2253135075840000$ $15516041180729376100$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $84$ $6750$ $571788$ $47476078$ $3939040644$ $326942580750$ $27136050989628$ $2252292264334558$ $186940255267540404$ $15516041174252898750$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 440 curves (of which all are hyperelliptic):

  • $y^2=38 x^6+36 x^5+42 x^4+4 x^3+30 x^2+78 x+4$
  • $y^2=76 x^6+72 x^5+x^4+8 x^3+60 x^2+73 x+8$
  • $y^2=52 x^6+18 x^5+34 x^4+73 x^3+44 x^2+2 x+78$
  • $y^2=38 x^6+42 x^5+80 x^4+66 x^3+74 x^2+26 x+17$
  • $y^2=76 x^6+x^5+77 x^4+49 x^3+65 x^2+52 x+34$
  • $y^2=35 x^6+80 x^5+21 x^4+61 x^3+35 x^2+67 x+13$
  • $y^2=79 x^6+38 x^5+51 x^4+5 x^3+7 x^2+81 x+23$
  • $y^2=75 x^6+76 x^5+19 x^4+10 x^3+14 x^2+79 x+46$
  • $y^2=31 x^6+37 x^5+23 x^4+34 x^3+15 x^2+49 x+6$
  • $y^2=47 x^6+6 x^5+71 x^4+69 x^3+39 x^2+10 x+64$
  • $y^2=11 x^6+12 x^5+59 x^4+55 x^3+78 x^2+20 x+45$
  • $y^2=74 x^6+34 x^5+10 x^4+11 x^3+54 x^2+22 x+11$
  • $y^2=65 x^6+68 x^5+20 x^4+22 x^3+25 x^2+44 x+22$
  • $y^2=30 x^6+9 x^5+53 x^4+66 x^3+56 x^2+50 x+31$
  • $y^2=60 x^6+18 x^5+23 x^4+49 x^3+29 x^2+17 x+62$
  • $y^2=68 x^6+6 x^5+68 x^4+14 x^3+31 x+22$
  • $y^2=53 x^6+12 x^5+53 x^4+28 x^3+62 x+44$
  • $y^2=52 x^6+52 x^5+46 x^4+61 x^3+33 x^2+69 x+40$
  • $y^2=21 x^6+21 x^5+9 x^4+39 x^3+66 x^2+55 x+80$
  • $y^2=8 x^6+2 x^5+52 x^4+80 x^3+42 x^2+69 x+33$
  • and 420 more

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{83^{2}}$.

Endomorphism algebra over $\F_{83}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-6}, \sqrt{59})\).
Endomorphism algebra over $\overline{\F}_{83}$
The base change of $A$ to $\F_{83^{2}}$ is 1.6889.acs 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-354}) \)$)$

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.83.a_cs$4$(not in LMFDB)