Properties

Label 2.61.c_bq
Base field $\F_{61}$
Dimension $2$
$p$-rank $2$
Ordinary yes
Supersingular no
Simple no
Geometrically simple no
Primitive yes
Principally polarizable yes
Contains a Jacobian yes

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Invariants

Base field:  $\F_{61}$
Dimension:  $2$
L-polynomial:  $( 1 - 8 x + 61 x^{2} )( 1 + 10 x + 61 x^{2} )$
  $1 + 2 x + 42 x^{2} + 122 x^{3} + 3721 x^{4}$
Frobenius angles:  $\pm0.328850104905$, $\pm0.721142061624$
Angle rank:  $2$ (numerical)
Jacobians:  $480$
Cyclic group of points:    no
Non-cyclic primes:   $2, 3$

This isogeny class is not 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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $3888$ $14152320$ $51547729968$ $191860171776000$ $713305415447698608$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $64$ $3802$ $227104$ $13856878$ $844551904$ $51519687082$ $3142744274944$ $191707303336798$ $11694146300773504$ $713342914034564602$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 480 curves (of which all are hyperelliptic):

  • $y^2=38 x^6+8 x^5+47 x^4+43 x^3+15 x^2+58 x+26$
  • $y^2=13 x^6+21 x^5+27 x^4+55 x^3+52 x^2+13 x+2$
  • $y^2=60 x^6+13 x^5+5 x^4+59 x^3+23 x^2+13 x+16$
  • $y^2=12 x^6+59 x^5+25 x^4+9 x^3+38 x^2+31 x+10$
  • $y^2=36 x^6+60 x^5+3 x^4+57 x^3+39 x^2+53$
  • $y^2=11 x^6+56 x^5+23 x^4+44 x^3+53 x^2+16 x+8$
  • $y^2=5 x^6+28 x^5+55 x^4+27 x^3+55 x^2+28 x+5$
  • $y^2=9 x^6+31 x^5+41 x^3+21 x+3$
  • $y^2=2 x^6+42 x^5+33 x^4+36 x^3+33 x^2+6 x+48$
  • $y^2=47 x^6+x^5+2 x^3+34 x^2+54 x+35$
  • $y^2=36 x^6+14 x^5+2 x^4+59 x^3+48 x^2+36 x+60$
  • $y^2=4 x^6+46 x^5+55 x^4+37 x^3+55 x^2+46 x+4$
  • $y^2=20 x^6+46 x^5+28 x^4+50 x^3+35 x^2+41 x+27$
  • $y^2=32 x^6+22 x^5+40 x^4+42 x^3+32 x^2+35 x+16$
  • $y^2=6 x^6+41 x^5+56 x^4+56 x^3+36 x^2+8 x+53$
  • $y^2=6 x^6+53 x^5+4 x^4+3 x^3+55 x^2+22 x+49$
  • $y^2=42 x^6+43 x^5+19 x^4+53 x^3+6 x^2+53 x+22$
  • $y^2=30 x^6+41 x^5+43 x^4+29 x^3+15 x^2+37 x+18$
  • $y^2=5 x^6+30 x^5+28 x^4+25 x^3+37 x^2+16 x+11$
  • $y^2=21 x^6+34 x^5+23 x^4+13 x^3+27 x^2+47 x+23$
  • and 460 more

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{61}$.

Endomorphism algebra over $\F_{61}$
The isogeny class factors as 1.61.ai $\times$ 1.61.k and its endomorphism algebra is a direct product of the endomorphism algebras for each isotypic factor. The endomorphism algebra for each factor is:

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.61.as_hu$2$(not in LMFDB)
2.61.ac_bq$2$(not in LMFDB)
2.61.s_hu$2$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.61.as_hu$2$(not in LMFDB)
2.61.ac_bq$2$(not in LMFDB)
2.61.s_hu$2$(not in LMFDB)
2.61.au_ik$4$(not in LMFDB)
2.61.ae_ba$4$(not in LMFDB)
2.61.e_ba$4$(not in LMFDB)
2.61.u_ik$4$(not in LMFDB)