Properties

Label 2.61.c_ek
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:  $( 1 - 2 x + 61 x^{2} )( 1 + 4 x + 61 x^{2} )$
  $1 + 2 x + 114 x^{2} + 122 x^{3} + 3721 x^{4}$
Frobenius angles:  $\pm0.459132412189$, $\pm0.582428998760$
Angle rank:  $2$ (numerical)
Jacobians:  $128$
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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $3960$ $14699520$ $51450224760$ $191565085409280$ $713360750968899000$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $64$ $3946$ $226672$ $13835566$ $844617424$ $51520707898$ $3142742168224$ $191707311969886$ $11694146051731552$ $713342910702594826$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 128 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

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

Endomorphism algebra over $\F_{61}$
The isogeny class factors as 1.61.ac $\times$ 1.61.e 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 is a list of all twists of this isogeny class.

TwistExtension degreeCommon base change
2.61.ag_fa$2$(not in LMFDB)
2.61.ac_ek$2$(not in LMFDB)
2.61.g_fa$2$(not in LMFDB)