Properties

Label 2.61.f_cu
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:  $( 1 - 5 x + 61 x^{2} )( 1 + 10 x + 61 x^{2} )$
  $1 + 5 x + 72 x^{2} + 305 x^{3} + 3721 x^{4}$
Frobenius angles:  $\pm0.396286106500$, $\pm0.721142061624$
Angle rank:  $2$ (numerical)
Jacobians:  $240$
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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $4104$ $14298336$ $51511093344$ $191776431600000$ $713277901651302504$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $67$ $3841$ $226942$ $13850833$ $844519327$ $51519969286$ $3142749030187$ $191707316097793$ $11694146041323862$ $713342911315264681$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 240 curves (of which all are hyperelliptic):

  • $y^2=49 x^6+32 x^5+42 x^4+40 x^3+29 x^2+22 x+35$
  • $y^2=44 x^6+16 x^5+18 x^4+32 x^3+60 x^2+30 x+54$
  • $y^2=18 x^6+32 x^5+49 x^4+50 x^3+31 x^2+31 x+23$
  • $y^2=15 x^6+9 x^5+11 x^4+36 x^3+x^2+26 x+56$
  • $y^2=28 x^6+23 x^5+34 x^4+55 x^3+13 x^2+9 x+36$
  • $y^2=9 x^6+x^5+31 x^4+17 x^3+4 x^2+43 x+34$
  • $y^2=20 x^6+7 x^5+9 x^4+35 x^3+57 x^2+45 x+15$
  • $y^2=33 x^6+39 x^5+2 x^4+37 x^3+32 x^2+47 x+30$
  • $y^2=51 x^6+14 x^5+51 x^4+36 x^3+29 x^2+40 x$
  • $y^2=31 x^6+56 x^5+24 x^4+51 x^3+42 x^2+31 x+18$
  • $y^2=38 x^6+33 x^5+7 x^4+57 x^3+39 x^2+6 x$
  • $y^2=20 x^6+11 x^5+19 x^4+34 x^3+10 x^2+43 x+56$
  • $y^2=56 x^6+29 x^5+16 x^4+42 x^3+3 x^2+59 x+3$
  • $y^2=53 x^6+21 x^5+55 x^4+56 x^3+43 x^2+35 x+14$
  • $y^2=3 x^6+8 x^5+24 x^4+51 x^3+49 x^2+59 x+23$
  • $y^2=21 x^6+22 x^5+42 x^4+29 x^3+55 x^2+46 x+11$
  • $y^2=37 x^6+41 x^5+45 x^4+40 x^3+18 x^2+57 x+6$
  • $y^2=49 x^6+37 x^5+10 x^4+30 x^3+44 x^2+11 x+6$
  • $y^2=48 x^6+32 x^5+x^4+37 x^3+27 x^2+41 x+38$
  • $y^2=40 x^6+30 x^5+24 x^4+60 x^3+43 x^2+34 x+37$
  • and 220 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.af $\times$ 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.ap_gq$2$(not in LMFDB)
2.61.af_cu$2$(not in LMFDB)
2.61.p_gq$2$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.61.ap_gq$2$(not in LMFDB)
2.61.af_cu$2$(not in LMFDB)
2.61.p_gq$2$(not in LMFDB)
2.61.ar_ha$4$(not in LMFDB)
2.61.ah_ck$4$(not in LMFDB)
2.61.h_ck$4$(not in LMFDB)
2.61.r_ha$4$(not in LMFDB)