Properties

Label 2.13.b_o
Base field $\F_{13}$
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:  $\F_{13}$
Dimension:  $2$
L-polynomial:  $( 1 - 3 x + 13 x^{2} )( 1 + 4 x + 13 x^{2} )$
  $1 + x + 14 x^{2} + 13 x^{3} + 169 x^{4}$
Frobenius angles:  $\pm0.363422825076$, $\pm0.687167041811$
Angle rank:  $2$ (numerical)
Jacobians:  $10$
Isomorphism classes:  63
Cyclic group of points:    no
Non-cyclic primes:   $3$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $198$ $33660$ $4818528$ $823996800$ $137569746798$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $15$ $197$ $2196$ $28849$ $370515$ $4819034$ $62763807$ $815785921$ $10604462868$ $137858870957$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 10 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{13}$.

Endomorphism algebra over $\F_{13}$
The isogeny class factors as 1.13.ad $\times$ 1.13.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 are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.13.ah_bm$2$2.169.bb_to
2.13.ab_o$2$2.169.bb_to
2.13.h_bm$2$2.169.bb_to

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

TwistExtension degreeCommon base change
2.13.ah_bm$2$2.169.bb_to
2.13.ab_o$2$2.169.bb_to
2.13.h_bm$2$2.169.bb_to
2.13.aj_bs$4$(not in LMFDB)
2.13.ad_i$4$(not in LMFDB)
2.13.d_i$4$(not in LMFDB)
2.13.j_bs$4$(not in LMFDB)