Properties

Label 2.83.a_cg
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:  $1 + 58 x^{2} + 6889 x^{4}$
Frobenius angles:  $\pm0.306806870789$, $\pm0.693193129211$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{3}, \sqrt{-14})\)
Galois group:  $C_2^2$
Jacobians:  $936$
Cyclic group of points:    no
Non-cyclic primes:   $2, 3$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $6948$ $48274704$ $326939369796$ $2253280897437696$ $15516041194904490468$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $84$ $7006$ $571788$ $47479150$ $3939040644$ $326938366222$ $27136050989628$ $2252292205069534$ $186940255267540404$ $15516041202603127486$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 936 curves (of which all are hyperelliptic):

  • $y^2=4 x^6+38 x^5+14 x^4+29 x^3+8 x^2+30 x+77$
  • $y^2=8 x^6+76 x^5+28 x^4+58 x^3+16 x^2+60 x+71$
  • $y^2=7 x^6+76 x^5+59 x^4+48 x^3+63 x^2+75 x+54$
  • $y^2=14 x^6+69 x^5+35 x^4+13 x^3+43 x^2+67 x+25$
  • $y^2=39 x^6+51 x^5+37 x^4+25 x^3+81 x^2+21 x+28$
  • $y^2=78 x^6+19 x^5+74 x^4+50 x^3+79 x^2+42 x+56$
  • $y^2=36 x^6+20 x^5+82 x^4+28 x^3+38 x^2+77 x+64$
  • $y^2=72 x^6+40 x^5+81 x^4+56 x^3+76 x^2+71 x+45$
  • $y^2=51 x^6+72 x^5+x^4+17 x^3+43 x^2+64 x+39$
  • $y^2=19 x^6+61 x^5+2 x^4+34 x^3+3 x^2+45 x+78$
  • $y^2=19 x^6+63 x^5+46 x^4+44 x^3+17 x^2+75 x+28$
  • $y^2=38 x^6+43 x^5+9 x^4+5 x^3+34 x^2+67 x+56$
  • $y^2=74 x^6+28 x^5+50 x^4+43 x^3+73 x^2+66 x+56$
  • $y^2=65 x^6+56 x^5+17 x^4+3 x^3+63 x^2+49 x+29$
  • $y^2=37 x^6+73 x^5+14 x^4+37 x^3+71 x^2+42 x+5$
  • $y^2=74 x^6+63 x^5+28 x^4+74 x^3+59 x^2+x+10$
  • $y^2=37 x^6+14 x^5+21 x^4+16 x^3+53 x^2+53 x+38$
  • $y^2=74 x^6+37 x^5+3 x^4+79 x^3+47 x^2+81 x+70$
  • $y^2=65 x^6+74 x^5+6 x^4+75 x^3+11 x^2+79 x+57$
  • $y^2=76 x^6+26 x^5+8 x^4+75 x^3+48 x^2+6 x+59$
  • and 916 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 \(\Q(\sqrt{3}, \sqrt{-14})\).
Endomorphism algebra over $\overline{\F}_{83}$
The base change of $A$ to $\F_{83^{2}}$ is 1.6889.cg 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-42}) \)$)$

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_acg$4$(not in LMFDB)
2.83.as_hj$12$(not in LMFDB)
2.83.s_hj$12$(not in LMFDB)