Abelian variety isogeny class 2.19.c_o over $\F_{19}$

• Label: 2.19.c_o
• Base field: $\F_{19}$
• Dimension: $2$
• $p$-rank: $2$
• Ordinary: yes
• Supersingular: no
• Simple: no
• Geometrically simple: no
• Primitive: yes
• Principally polarizable: yes
• Contains a Jacobian: yes

Invariants

Base field:	$\F_{19}$
Dimension:	$2$
L-polynomial:	$( 1 - 4 x + 19 x^{2} )( 1 + 6 x + 19 x^{2} )$
	$1 + 2 x + 14 x^{2} + 38 x^{3} + 361 x^{4}$
Frobenius angles:	$\pm0.348268167089$, $\pm0.741619551917$
Angle rank:	$2$ (numerical)
Jacobians:	$48$
Cyclic group of points:	no
Non-cyclic primes:	$2$

This isogeny class is not 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

$r$	$1$	$2$	$3$	$4$	$5$
$A(\F_{q^r})$	$416$	$139776$	$47299616$	$17108582400$	$6120977816096$

Point counts of the curve

$r$	$1$	$2$	$3$	$4$	$5$	$6$	$7$	$8$	$9$	$10$
$C(\F_{q^r})$	$22$	$386$	$6898$	$131278$	$2472022$	$47030546$	$893909458$	$16983512158$	$322689326422$	$6131067815906$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 48 curves (of which all are hyperelliptic):

• $y^2=6 x^6+15 x^5+13 x^4+12 x^3+2 x^2+4 x+10$
• $y^2=9 x^6+12 x^5+9 x^4+10 x^3+8 x^2+16$
• $y^2=15 x^6+10 x^5+11 x^4+8 x^3+6 x^2+14 x+5$
• $y^2=8 x^6+17 x^5+9 x^4+2 x^3+16 x^2+x+15$
• $y^2=6 x^6+17 x^5+9 x^4+9 x^3+17 x^2+6 x+4$
• $y^2=15 x^6+14 x^5+4 x^4+14 x^3+11 x^2+14 x+14$
• $y^2=5 x^6+2 x^5+12 x^4+8 x^3+7 x^2+7 x+12$
• $y^2=9 x^6+4 x^5+10 x^4+3 x^3+9 x^2+13 x+17$
• $y^2=5 x^6+17 x^5+7 x^4+17 x^3+9 x^2+9 x+18$
• $y^2=18 x^6+13 x^5+11 x^4+13 x^3+7 x^2+7 x+16$
• $y^2=15 x^6+5 x^5+6 x^4+3 x^3+14 x^2+11 x+13$
• $y^2=13 x^6+10 x^5+17 x^4+6 x^3+18 x^2+4 x+10$
• $y^2=10 x^6+4 x^5+17 x^4+15 x^3+16 x^2+16 x+8$
• $y^2=13 x^6+4 x^4+13 x^3+4 x^2+13$
• $y^2=3 x^6+16 x^5+12 x^4+x^3+13 x^2+4 x+2$
• $y^2=7 x^5+8 x^4+4 x^3+16 x^2+15 x+18$
• $y^2=x^6+18 x^5+x^4+16 x^3+17 x^2+3 x+12$
• $y^2=11 x^6+15 x^5+18 x^3+1$
• $y^2=18 x^5+7 x^4+6 x^3+4 x^2+4 x$
• $y^2=17 x^6+12 x^5+18 x^4+5 x^3+18 x^2+12 x+17$
• and

• $y^2=2 x^6+9 x^5+x^4+9 x^3+17 x^2+15 x+5$
• $y^2=12 x^6+x^5+16 x^4+15 x^3+15 x^2+8 x+18$
• $y^2=18 x^6+7 x^5+12 x^4+4 x^3+x^2+11 x+3$
• $y^2=5 x^6+8 x^5+4 x^4+13 x^3+4 x^2+9 x+11$
• $y^2=x^6+15 x^5+3 x^4+14 x^3+10 x^2+15 x+15$
• $y^2=11 x^6+3 x^5+6 x^4+17 x^3+16 x^2+15 x+2$
• $y^2=x^6+3 x^5+9 x^4+4 x^3+11 x^2+12 x$
• $y^2=5 x^6+11 x^5+18 x^4+3 x^3+2 x^2+6 x+17$
• $y^2=4 x^6+6 x^5+15 x^4+18 x^3+4 x^2+10 x+6$
• $y^2=16 x^6+5 x^5+5 x^4+3 x^3+5 x^2+5 x+16$
• $y^2=7 x^6+7 x^5+9 x^4+6 x^3+12 x^2+4 x+16$
• $y^2=12 x^6+11 x^5+13 x^4+14 x^3+4 x^2+11 x+5$
• $y^2=4 x^6+6 x^5+15 x^4+4 x^3+2 x^2+16 x+16$
• $y^2=2 x^6+18 x^5+8 x^4+15 x^3+10 x^2+4 x+9$
• $y^2=11 x^6+14 x^5+14 x^4+x^3+14 x^2+4 x+2$
• $y^2=x^6+9 x^5+13 x^4+x^3+12 x^2+14 x+15$
• $y^2=18 x^6+6 x^5+14 x^4+11 x^3+5 x^2+11 x+16$
• $y^2=5 x^6+15 x^5+16 x^3+17 x^2+10 x+13$
• $y^2=2 x^6+3 x^5+4 x^4+16 x^3+9 x^2+2 x+8$
• $y^2=2 x^5+10 x^4+12 x^3+17 x^2+11$
• $y^2=14 x^6+15 x^5+3 x^4+13 x^3+16 x+17$
• $y^2=13 x^6+9 x^5+9 x^4+2 x^3+9 x^2+9 x+13$
• $y^2=x^6+8 x^5+15 x^4+17 x^3+4 x^2+11$
• $y^2=8 x^6+7 x^5+15 x^4+3 x^3+3 x^2+7 x+15$
• $y^2=x^6+13 x^5+16 x^4+18 x^3+9 x^2+x+3$
• $y^2=18 x^6+2 x^5+18 x^4+3 x^3+12 x^2+18 x+17$
• $y^2=16 x^6+18 x^5+9 x^4+6 x^3+17 x^2+13 x+3$
• $y^2=15 x^6+17 x^5+14 x^4+15 x^3+14 x^2+17 x+15$

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{19}$.

Endomorphism algebra over $\F_{19}$

The isogeny class factors as 1.19.ae $\times$ 1.19.g and its endomorphism algebra is a direct product of the endomorphism algebras for each isotypic factor. The endomorphism algebra for each factor is:

• 1.19.ae : \(\Q(\sqrt{-15}) \).
• 1.19.g : \(\Q(\sqrt{-10}) \).

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
2.19.ak_ck	$2$	(not in LMFDB)
2.19.ac_o	$2$	(not in LMFDB)
2.19.k_ck	$2$	(not in LMFDB)