Properties

Label 2.13.b_am
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:  $1 + x - 12 x^{2} + 13 x^{3} + 169 x^{4}$
Frobenius angles:  $\pm0.210951023905$, $\pm0.877617690571$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{-3}, \sqrt{17})\)
Galois group:  $C_2^2$
Jacobians:  $10$
Isomorphism classes:  18

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $172$ $24768$ $4999696$ $823981824$ $138148711132$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $15$ $145$ $2274$ $28849$ $372075$ $4832710$ $62735415$ $815755969$ $10604108202$ $137858359225$

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 $\F_{13^{3}}$.

Endomorphism algebra over $\F_{13}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-3}, \sqrt{17})\).
Endomorphism algebra over $\overline{\F}_{13}$
The base change of $A$ to $\F_{13^{3}}$ is 1.2197.bm 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-51}) \)$)$

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.ab_am$2$2.169.az_ro
2.13.ac_bb$3$(not in LMFDB)
2.13.ab_am$6$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.13.ab_am$2$2.169.az_ro
2.13.ac_bb$3$(not in LMFDB)
2.13.ab_am$6$(not in LMFDB)
2.13.a_z$6$(not in LMFDB)
2.13.c_bb$6$(not in LMFDB)
2.13.a_az$12$(not in LMFDB)