Properties

Label 2.83.a_cq
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:  $1 + 68 x^{2} + 6889 x^{4}$
Frobenius angles:  $\pm0.317172587130$, $\pm0.682827412870$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{2}, \sqrt{-13})\)
Galois group:  $C_2^2$
Jacobians:  $343$
Cyclic group of points:    no
Non-cyclic primes:   $7$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $6958$ $48413764$ $326939282446$ $2253161277810576$ $15516041193965005918$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $84$ $7026$ $571788$ $47476630$ $3939040644$ $326938191522$ $27136050989628$ $2252292254380894$ $186940255267540404$ $15516041200724158386$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 343 curves (of which all are hyperelliptic):

  • $y^2=20 x^6+30 x^5+21 x^4+72 x^3+78 x^2+18 x+52$
  • $y^2=40 x^6+60 x^5+42 x^4+61 x^3+73 x^2+36 x+21$
  • $y^2=28 x^6+26 x^5+81 x^4+59 x^3+37 x^2+74 x+24$
  • $y^2=56 x^6+52 x^5+79 x^4+35 x^3+74 x^2+65 x+48$
  • $y^2=52 x^6+24 x^5+38 x^4+48 x^3+75 x^2+47 x+63$
  • $y^2=21 x^6+48 x^5+76 x^4+13 x^3+67 x^2+11 x+43$
  • $y^2=45 x^6+38 x^5+63 x^4+43 x^3+30 x^2+75 x+70$
  • $y^2=7 x^6+76 x^5+43 x^4+3 x^3+60 x^2+67 x+57$
  • $y^2=80 x^6+28 x^5+19 x^4+42 x^3+21 x^2+64 x+47$
  • $y^2=77 x^6+56 x^5+38 x^4+x^3+42 x^2+45 x+11$
  • $y^2=25 x^6+67 x^5+30 x^4+36 x^3+47 x^2+74 x+60$
  • $y^2=50 x^6+51 x^5+60 x^4+72 x^3+11 x^2+65 x+37$
  • $y^2=37 x^6+60 x^5+4 x^4+77 x^3+61 x^2+10 x+7$
  • $y^2=74 x^6+37 x^5+8 x^4+71 x^3+39 x^2+20 x+14$
  • $y^2=13 x^6+23 x^5+39 x^4+23 x^3+35 x^2+56 x+21$
  • $y^2=26 x^6+46 x^5+78 x^4+46 x^3+70 x^2+29 x+42$
  • $y^2=61 x^6+32 x^5+x^4+66 x^3+61 x^2+44 x+14$
  • $y^2=39 x^6+64 x^5+2 x^4+49 x^3+39 x^2+5 x+28$
  • $y^2=14 x^6+3 x^5+56 x^4+38 x^3+43 x^2+6 x+23$
  • $y^2=28 x^6+6 x^5+29 x^4+76 x^3+3 x^2+12 x+46$
  • and 323 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 \(\Q(\sqrt{2}, \sqrt{-13})\).
Endomorphism algebra over $\overline{\F}_{83}$
The base change of $A$ to $\F_{83^{2}}$ is 1.6889.cq 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-13}) \)$)$

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_acq$4$(not in LMFDB)
2.83.ao_du$8$(not in LMFDB)
2.83.o_du$8$(not in LMFDB)