Abelian variety isogeny class 1.256.z over $\F_{2^{8}}$

• Label: 1.256.z
• Base field: $\F_{2^{8}}$
• Dimension: $1$
• $p$-rank: $1$
• Ordinary: yes
• Supersingular: no
• Simple: yes
• Geometrically simple: yes
• Primitive: yes
• Principally polarizable: yes
• Contains a Jacobian: yes

Invariants

Base field:	$\F_{2^{8}}$
Dimension:	$1$
L-polynomial:	$1 + 25 x + 256 x^{2}$
Frobenius angles:	$\pm0.785417595150$
Angle rank:	$1$ (numerical)
Number field:	\(\Q(\sqrt{-399}) \)
Galois group:	$C_2$
Jacobians:	$16$

This isogeny class is simple and geometrically simple, primitive, ordinary, and not supersingular. It is principally polarizable and contains a Jacobian.

Newton polygon

This isogeny class is ordinary.

$p$-rank:	$1$
Slopes:	$[0, 1]$

Point counts

Point counts of the abelian variety

$r$	$1$	$2$	$3$	$4$	$5$
$A(\F_{q^r})$	$282$	$65424$	$16773642$	$4295085600$	$1099509585402$

Point counts of the curve

$r$	$1$	$2$	$3$	$4$	$5$	$6$	$7$	$8$	$9$	$10$
$C(\F_{q^r})$	$282$	$65424$	$16773642$	$4295085600$	$1099509585402$	$281474997484464$	$72057594041430762$	$18446744068303886400$	$4722366483003890120922$	$1208925819612656902321104$

Jacobians and polarizations

This isogeny class contains the Jacobians of 16 curves (of which all are hyperelliptic), and hence is principally polarizable:

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{2^{8}}$.

Endomorphism algebra over $\F_{2^{8}}$

The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-399}) \).

Base change

This is a primitive isogeny class.

Twists

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

Twist	Extension degree	Common base change
1.256.az	$2$	(not in LMFDB)