Properties

Label 2.71.a_aby
Base field $\F_{71}$
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:  $\F_{71}$
Dimension:  $2$
L-polynomial:  $1 - 50 x^{2} + 5041 x^{4}$
Frobenius angles:  $\pm0.192731693382$, $\pm0.807268306618$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{3}, \sqrt{-23})\)
Galois group:  $C_2^2$
Jacobians:  $612$
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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $4992$ $24920064$ $128100915072$ $646138982301696$ $3255243547495085952$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $72$ $4942$ $357912$ $25426846$ $1804229352$ $128101546222$ $9095120158392$ $645753517919038$ $45848500718449032$ $3255243543980290702$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 612 curves (of which all are hyperelliptic):

  • $y^2=18 x^6+49 x^5+57 x^4+20 x^3+56 x^2+42 x+7$
  • $y^2=55 x^6+59 x^5+44 x^4+69 x^3+37 x^2+10 x+49$
  • $y^2=41 x^6+19 x^5+61 x^4+12 x^3+22 x^2+17 x+57$
  • $y^2=3 x^6+62 x^5+x^4+13 x^3+12 x^2+48 x+44$
  • $y^2=4 x^6+57 x^5+36 x^4+35 x^3+65 x^2+48 x+5$
  • $y^2=28 x^6+44 x^5+39 x^4+32 x^3+29 x^2+52 x+35$
  • $y^2=25 x^6+65 x^5+24 x^4+40 x^3+23 x^2+49 x+26$
  • $y^2=12 x^6+2 x^5+51 x^4+62 x^3+56 x^2+32 x+52$
  • $y^2=13 x^6+14 x^5+2 x^4+8 x^3+37 x^2+11 x+9$
  • $y^2=49 x^6+47 x^5+17 x^4+22 x^3+53 x^2+34 x+54$
  • $y^2=59 x^6+45 x^5+48 x^4+12 x^3+16 x^2+25 x+23$
  • $y^2=6 x^6+25 x^5+25 x^4+28 x^3+70 x^2+8 x+7$
  • $y^2=32 x^6+18 x^5+58 x^4+19 x^3+35 x^2+36 x+39$
  • $y^2=11 x^6+55 x^5+51 x^4+62 x^3+32 x^2+39 x+60$
  • $y^2=28 x^6+11 x^5+69 x^4+8 x^3+42 x^2+56 x+64$
  • $y^2=54 x^6+6 x^5+57 x^4+56 x^3+10 x^2+37 x+22$
  • $y^2=50 x^6+5 x^5+4 x^4+4 x^3+64 x^2+41 x+48$
  • $y^2=66 x^6+35 x^5+28 x^4+28 x^3+22 x^2+3 x+52$
  • $y^2=25 x^6+46 x^5+59 x^4+5 x^3+64 x^2+10 x+46$
  • $y^2=33 x^6+38 x^5+58 x^4+35 x^3+22 x^2+70 x+38$
  • and 592 more

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{71^{2}}$.

Endomorphism algebra over $\F_{71}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{3}, \sqrt{-23})\).
Endomorphism algebra over $\overline{\F}_{71}$
The base change of $A$ to $\F_{71^{2}}$ is 1.5041.aby 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-69}) \)$)$

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.71.a_by$4$(not in LMFDB)
2.71.ay_kd$12$(not in LMFDB)
2.71.y_kd$12$(not in LMFDB)