Properties

Label 2.79.a_afe
Base field $\F_{79}$
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:  $\F_{79}$
Dimension:  $2$
L-polynomial:  $1 - 134 x^{2} + 6241 x^{4}$
Frobenius angles:  $\pm0.0888729187302$, $\pm0.911127081270$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{-6}, \sqrt{73})\)
Galois group:  $C_2^2$
Jacobians:  $44$
Isomorphism classes:  80
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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $6108$ $37307664$ $243087558300$ $1516682492273664$ $9468276088408764828$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $80$ $5974$ $493040$ $38939134$ $3077056400$ $243087661078$ $19203908986160$ $1517108905777534$ $119851595982618320$ $9468276094190682454$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 44 curves (of which all are hyperelliptic):

  • $y^2=31 x^6+5 x^5+28 x^4+40 x^3+2 x^2+23 x+70$
  • $y^2=23 x^6+57 x^5+41 x^4+31 x^2+67 x+16$
  • $y^2=69 x^6+13 x^5+44 x^4+14 x^2+43 x+48$
  • $y^2=5 x^6+70 x^5+75 x^4+77 x^3+51 x^2+33 x+56$
  • $y^2=61 x^6+56 x^5+51 x^4+12 x^3+43 x^2+70 x+67$
  • $y^2=9 x^6+44 x^5+36 x^4+7 x^3+71 x^2+50 x+7$
  • $y^2=27 x^6+53 x^5+29 x^4+21 x^3+55 x^2+71 x+21$
  • $y^2=28 x^6+68 x^5+57 x^4+47 x^3+32 x^2+27 x+51$
  • $y^2=13 x^6+56 x^5+64 x^4+46 x^3+12 x^2+39 x+30$
  • $y^2=48 x^6+40 x^5+55 x^4+73 x^3+24 x^2+40 x+31$
  • $y^2=68 x^6+3 x^5+59 x^4+46 x^3+51 x^2+28 x+9$
  • $y^2=73 x^6+77 x^5+56 x^4+37 x^2+64 x+59$
  • $y^2=61 x^6+73 x^5+10 x^4+32 x^2+34 x+19$
  • $y^2=42 x^6+76 x^5+37 x^4+69 x^3+52 x^2+35 x+48$
  • $y^2=47 x^6+70 x^5+32 x^4+49 x^3+77 x^2+26 x+65$
  • $y^2=71 x^6+19 x^5+64 x^4+14 x^3+24 x^2+58 x+55$
  • $y^2=55 x^6+57 x^5+34 x^4+42 x^3+72 x^2+16 x+7$
  • $y^2=43 x^6+18 x^5+59 x^4+69 x^3+17 x^2+23 x+17$
  • $y^2=50 x^6+54 x^5+19 x^4+49 x^3+51 x^2+69 x+51$
  • $y^2=61 x^6+42 x^5+75 x^4+15 x^3+16 x^2+6 x$
  • and 24 more

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{79^{2}}$.

Endomorphism algebra over $\F_{79}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-6}, \sqrt{73})\).
Endomorphism algebra over $\overline{\F}_{79}$
The base change of $A$ to $\F_{79^{2}}$ is 1.6241.afe 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-438}) \)$)$

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.79.a_fe$4$(not in LMFDB)