Properties

Label 2.256.acf_bym
Base field $\F_{2^{8}}$
Dimension $2$
$p$-rank $1$
Ordinary no
Supersingular no
Simple no
Geometrically simple no
Primitive yes
Principally polarizable yes
Contains a Jacobian no

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Invariants

Base field:  $\F_{2^{8}}$
Dimension:  $2$
L-polynomial:  $( 1 - 16 x )^{2}( 1 - 25 x + 256 x^{2} )$
  $1 - 57 x + 1312 x^{2} - 14592 x^{3} + 65536 x^{4}$
Frobenius angles:  $0$, $0$, $\pm0.214582404850$
Angle rank:  $1$ (numerical)

This isogeny class is not simple, primitive, not ordinary, and not supersingular. It is principally polarizable.

Newton polygon

$p$-rank:  $1$
Slopes:  $[0, 1/2, 1/2, 1]$

Point counts

Point counts of the abelian variety

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $52200$ $4254195600$ $281397520567800$ $18446689224355860000$ $1208925759384596592405000$

Point counts of the (virtual) curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $200$ $64912$ $16772600$ $4294954528$ $1099511573000$ $281474963930032$ $72057593497554200$ $18446744059713951808$ $4722366482597961353000$ $1208925819610457879065552$

Jacobians and polarizations

This isogeny class is principally polarizable, but does not contain a Jacobian.

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{2^{8}}$.

Endomorphism algebra over $\F_{2^{8}}$
The isogeny class factors as 1.256.abg $\times$ 1.256.az 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
2.256.ah_alc$2$(not in LMFDB)
2.256.h_alc$2$(not in LMFDB)
2.256.cf_bym$2$(not in LMFDB)
2.256.aj_ei$3$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.256.ah_alc$2$(not in LMFDB)
2.256.h_alc$2$(not in LMFDB)
2.256.cf_bym$2$(not in LMFDB)
2.256.aj_ei$3$(not in LMFDB)
2.256.az_ts$4$(not in LMFDB)
2.256.z_ts$4$(not in LMFDB)
2.256.abp_bjc$6$(not in LMFDB)
2.256.j_ei$6$(not in LMFDB)
2.256.bp_bjc$6$(not in LMFDB)