Properties

Label 2.19.a_abd
Base field $\F_{19}$
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:  $\F_{19}$
Dimension:  $2$
L-polynomial:  $1 - 29 x^{2} + 361 x^{4}$
Frobenius angles:  $\pm0.111823923823$, $\pm0.888176076177$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(i, \sqrt{67})\)
Galois group:  $C_2^2$
Jacobians:  $6$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $333$ $110889$ $47052900$ $16952821209$ $6131070872253$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $20$ $304$ $6860$ $130084$ $2476100$ $47059918$ $893871740$ $16984056004$ $322687697780$ $6131075486704$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 6 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{19^{2}}$.

Endomorphism algebra over $\F_{19}$
The endomorphism algebra of this simple isogeny class is \(\Q(i, \sqrt{67})\).
Endomorphism algebra over $\overline{\F}_{19}$
The base change of $A$ to $\F_{19^{2}}$ is 1.361.abd 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-67}) \)$)$

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.19.ag_bv$4$(not in LMFDB)
2.19.a_bd$4$(not in LMFDB)
2.19.g_bv$4$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.19.ag_bv$4$(not in LMFDB)
2.19.a_bd$4$(not in LMFDB)
2.19.g_bv$4$(not in LMFDB)
2.19.ad_ak$12$(not in LMFDB)
2.19.d_ak$12$(not in LMFDB)