Properties

Label 2.7.a_c
Base field $\F_{7}$
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:  $\F_{7}$
Dimension:  $2$
L-polynomial:  $1 + 2 x^{2} + 49 x^{4}$
Frobenius angles:  $\pm0.272814474171$, $\pm0.727185525829$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\zeta_{12})\)
Galois group:  $C_2^2$
Jacobians:  $10$
Cyclic group of points:    no
Non-cyclic primes:   $2$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $52$ $2704$ $117364$ $6230016$ $282497332$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $8$ $54$ $344$ $2590$ $16808$ $117078$ $823544$ $5756734$ $40353608$ $282519414$

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 $\F_{7^{2}}$.

Endomorphism algebra over $\F_{7}$
The endomorphism algebra of this simple isogeny class is \(\Q(\zeta_{12})\).
Endomorphism algebra over $\overline{\F}_{7}$
The base change of $A$ to $\F_{7^{2}}$ is 1.49.c 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
2.7.a_an$3$2.343.a_ala
2.7.a_l$3$2.343.a_ala
2.7.ai_be$4$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.7.a_an$3$2.343.a_ala
2.7.a_l$3$2.343.a_ala
2.7.ai_be$4$(not in LMFDB)
2.7.a_ac$4$(not in LMFDB)
2.7.i_be$4$(not in LMFDB)
2.7.ak_bn$12$(not in LMFDB)
2.7.aj_bi$12$(not in LMFDB)
2.7.ag_t$12$(not in LMFDB)
2.7.af_s$12$(not in LMFDB)
2.7.ae_j$12$(not in LMFDB)
2.7.ad_k$12$(not in LMFDB)
2.7.ac_p$12$(not in LMFDB)
2.7.ab_ag$12$(not in LMFDB)
2.7.a_al$12$(not in LMFDB)
2.7.a_n$12$(not in LMFDB)
2.7.b_ag$12$(not in LMFDB)
2.7.c_p$12$(not in LMFDB)
2.7.d_k$12$(not in LMFDB)
2.7.e_j$12$(not in LMFDB)
2.7.f_s$12$(not in LMFDB)
2.7.g_t$12$(not in LMFDB)
2.7.j_bi$12$(not in LMFDB)
2.7.k_bn$12$(not in LMFDB)