Properties

Label 2.71.a_abq
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:  $1 - 42 x^{2} + 5041 x^{4}$
Frobenius angles:  $\pm0.202211126514$, $\pm0.797788873486$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(i, \sqrt{46})\)
Galois group:  $C_2^2$
Jacobians:  $246$
Cyclic group of points:    no
Non-cyclic primes:   $2, 5$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $5000$ $25000000$ $128100845000$ $646176400000000$ $3255243547410125000$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $72$ $4958$ $357912$ $25428318$ $1804229352$ $128101406078$ $9095120158392$ $645753494514238$ $45848500718449032$ $3255243543810368798$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 246 curves (of which all are hyperelliptic):

  • $y^2=64 x^6+45 x^5+57 x^4+17 x^3+4 x^2+56 x+20$
  • $y^2=22 x^6+31 x^5+44 x^4+48 x^3+28 x^2+37 x+69$
  • $y^2=44 x^6+17 x^5+28 x^4+68 x^3+50 x^2+43 x+37$
  • $y^2=21 x^6+23 x^5+6 x^4+8 x^3+24 x^2+4 x+28$
  • $y^2=8 x^6+27 x^5+65 x^4+51 x^2+20 x+56$
  • $y^2=56 x^6+47 x^5+29 x^4+2 x^2+69 x+37$
  • $y^2=3 x^6+9 x^5+3 x^4+37 x^3+5 x^2+26 x+55$
  • $y^2=21 x^6+63 x^5+21 x^4+46 x^3+35 x^2+40 x+30$
  • $y^2=47 x^6+28 x^5+4 x^4+49 x^3+42 x^2+28 x+43$
  • $y^2=45 x^6+54 x^5+28 x^4+59 x^3+10 x^2+54 x+17$
  • $y^2=64 x^6+62 x^5+5 x^4+57 x^3+9 x^2+49 x+49$
  • $y^2=22 x^6+8 x^5+35 x^4+44 x^3+63 x^2+59 x+59$
  • $y^2=9 x^6+64 x^5+63 x^4+34 x^3+29 x^2+43 x$
  • $y^2=29 x^6+10 x^5+35 x^4+23 x^3+3 x^2+9 x+12$
  • $y^2=61 x^6+70 x^5+32 x^4+19 x^3+21 x^2+63 x+13$
  • $y^2=60 x^6+33 x^5+50 x^4+32 x^3+24 x^2+15 x+62$
  • $y^2=65 x^6+18 x^5+66 x^4+11 x^3+26 x^2+34 x+8$
  • $y^2=33 x^6+43 x^5+60 x^4+52 x^3+69 x^2+61 x+46$
  • $y^2=18 x^6+17 x^5+65 x^4+9 x^3+57 x^2+x+38$
  • $y^2=26 x^6+8 x^5+25 x^3+23 x^2+35 x+42$
  • and 226 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 \(\Q(i, \sqrt{46})\).
Endomorphism algebra over $\overline{\F}_{71}$
The base change of $A$ to $\F_{71^{2}}$ is 1.5041.abq 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-46}) \)$)$

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.71.au_ji$4$(not in LMFDB)
2.71.a_bq$4$(not in LMFDB)
2.71.u_ji$4$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.71.au_ji$4$(not in LMFDB)
2.71.a_bq$4$(not in LMFDB)
2.71.u_ji$4$(not in LMFDB)
2.71.ak_bd$12$(not in LMFDB)
2.71.k_bd$12$(not in LMFDB)