Invariants
Base field: | $\F_{2^{2}}$ |
Dimension: | $2$ |
L-polynomial: | $1 - x + 4 x^{2} - 4 x^{3} + 16 x^{4}$ |
Frobenius angles: | $\pm0.278773483733$, $\pm0.627659203843$ |
Angle rank: | $2$ (numerical) |
Number field: | 4.0.2312.1 |
Galois group: | $D_{4}$ |
Jacobians: | $1$ |
This isogeny class is simple and geometrically simple, not primitive, not ordinary, and not supersingular. It is principally polarizable and contains a Jacobian.
Newton polygon
$p$-rank: | $1$ |
Slopes: | $[0, 1/2, 1/2, 1]$ |
Point counts
Point counts of the abelian variety
$r$ | $1$ | $2$ | $3$ | $4$ | $5$ |
---|---|---|---|---|---|
$A(\F_{q^r})$ | $16$ | $416$ | $3952$ | $74048$ | $1132816$ |
$r$ | $1$ | $2$ | $3$ | $4$ | $5$ | $6$ | $7$ | $8$ | $9$ | $10$ |
---|---|---|---|---|---|---|---|---|---|---|
$C(\F_{q^r})$ | $4$ | $24$ | $64$ | $288$ | $1104$ | $3936$ | $16048$ | $65664$ | $261712$ | $1048864$ |
Jacobians and polarizations
This isogeny class contains the Jacobian of 1 curve (which is hyperelliptic), and hence is principally polarizable:
- $y^2+xy=x^5+x$
Decomposition and endomorphism algebra
All geometric endomorphisms are defined over $\F_{2^{2}}$.
Endomorphism algebra over $\F_{2^{2}}$The endomorphism algebra of this simple isogeny class is 4.0.2312.1. |
Base change
This isogeny class is not primitive. It is a base change from the following isogeny classes over subfields of $\F_{2^{2}}$.
Subfield | Primitive Model |
$\F_{2}$ | 2.2.ab_a |
$\F_{2}$ | 2.2.b_a |
Twists
Below is a list of all twists of this isogeny class.
Twist | Extension degree | Common base change |
---|---|---|
2.4.b_e | $2$ | 2.16.h_bo |