Properties

Label 2.5.ac_l
Base field $\F_{5}$
Dimension $2$
$p$-rank $2$
Ordinary yes
Supersingular no
Simple no
Geometrically simple no
Primitive yes
Principally polarizable yes
Contains a Jacobian yes

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Invariants

Base field:  $\F_{5}$
Dimension:  $2$
L-polynomial:  $( 1 - x + 5 x^{2} )^{2}$
  $1 - 2 x + 11 x^{2} - 10 x^{3} + 25 x^{4}$
Frobenius angles:  $\pm0.428216853436$, $\pm0.428216853436$
Angle rank:  $1$ (numerical)
Jacobians:  $1$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $25$ $1225$ $19600$ $354025$ $9150625$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $4$ $44$ $154$ $564$ $2924$ $15734$ $79244$ $391204$ $1948114$ $9757724$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobian of 1 curve (which is hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{5}$.

Endomorphism algebra over $\F_{5}$
The isogeny class factors as 1.5.ab 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-19}) \)$)$

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.5.a_j$2$2.25.s_fb
2.5.c_l$2$2.25.s_fb
2.5.b_ae$3$2.125.bc_re

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

TwistExtension degreeCommon base change
2.5.a_j$2$2.25.s_fb
2.5.c_l$2$2.25.s_fb
2.5.b_ae$3$2.125.bc_re
2.5.a_aj$4$2.625.ack_dhb
2.5.ab_ae$6$(not in LMFDB)