Properties

Label 2.13.a_ab
Base field $\F_{13}$
Dimension $2$
$p$-rank $2$
Ordinary yes
Supersingular no
Simple yes
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:  $1 - x^{2} + 169 x^{4}$
Frobenius angles:  $\pm0.243877145822$, $\pm0.756122854178$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\zeta_{12})\)
Galois group:  $C_2^2$
Jacobians:  $12$
Cyclic group of points:    yes

This isogeny class is simple but not geometrically 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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $169$ $28561$ $4827316$ $835152201$ $137858349889$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $14$ $168$ $2198$ $29236$ $371294$ $4827822$ $62748518$ $815617828$ $10604499374$ $137858207928$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 12 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{13^{2}}$.

Endomorphism algebra over $\F_{13}$
The endomorphism algebra of this simple isogeny class is \(\Q(\zeta_{12})\).
Endomorphism algebra over $\overline{\F}_{13}$
The base change of $A$ to $\F_{13^{2}}$ is 1.169.ab 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-3}) \)$)$

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.a_aw$3$(not in LMFDB)
2.13.a_x$3$(not in LMFDB)
2.13.ak_bz$4$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.13.a_aw$3$(not in LMFDB)
2.13.a_x$3$(not in LMFDB)
2.13.ak_bz$4$(not in LMFDB)
2.13.a_b$4$(not in LMFDB)
2.13.k_bz$4$(not in LMFDB)
2.13.ao_cx$12$(not in LMFDB)
2.13.am_cj$12$(not in LMFDB)
2.13.aj_bo$12$(not in LMFDB)
2.13.ah_bk$12$(not in LMFDB)
2.13.af_m$12$(not in LMFDB)
2.13.ae_be$12$(not in LMFDB)
2.13.ad_q$12$(not in LMFDB)
2.13.ac_aj$12$(not in LMFDB)
2.13.a_ax$12$(not in LMFDB)
2.13.a_w$12$(not in LMFDB)
2.13.c_aj$12$(not in LMFDB)
2.13.d_q$12$(not in LMFDB)
2.13.e_be$12$(not in LMFDB)
2.13.f_m$12$(not in LMFDB)
2.13.h_bk$12$(not in LMFDB)
2.13.j_bo$12$(not in LMFDB)
2.13.m_cj$12$(not in LMFDB)
2.13.o_cx$12$(not in LMFDB)