Properties

Label 2.31.ac_cc
Base field F31\F_{31}
Dimension 22
pp-rank 22
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:  F31\F_{31}
Dimension:  22
L-polynomial:  (14x+31x2)(1+2x+31x2)( 1 - 4 x + 31 x^{2} )( 1 + 2 x + 31 x^{2} )
  12x+54x262x3+961x41 - 2 x + 54 x^{2} - 62 x^{3} + 961 x^{4}
Frobenius angles:  ±0.383045975359\pm0.383045975359, ±0.557482058976\pm0.557482058976
Angle rank:  22 (numerical)
Jacobians:  9292

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.

pp-rank:  22
Slopes:  [0,0,1,1][0, 0, 1, 1]

Point counts

Point counts of the abelian variety

rr 11 22 33 44 55
A(Fqr)A(\F_{q^r}) 952952 10281601028160 891381400891381400 851382282240851382282240 819573232266712819573232266712

Point counts of the curve

rr 11 22 33 44 55 66 77 88 99 1010
C(Fqr)C(\F_{q^r}) 3030 10661066 2992229922 921886921886 2862723028627230 887496298887496298 2751247677027512476770 852892614526852892614526 2643963412054226439634120542 819628224318826819628224318826

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 92 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over F31\F_{31}.

Endomorphism algebra over F31\F_{31}
The isogeny class factors as 1.31.ae ×\times 1.31.c and its endomorphism algebra is a direct product of the endomorphism algebras for each isotypic factor. The endomorphism algebra for each factor is:

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.31.ag_cs22(not in LMFDB)
2.31.c_cc22(not in LMFDB)
2.31.g_cs22(not in LMFDB)
2.31.af_bw33(not in LMFDB)
2.31.n_dg33(not in LMFDB)

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

TwistExtension degreeCommon base change
2.31.ag_cs22(not in LMFDB)
2.31.c_cc22(not in LMFDB)
2.31.g_cs22(not in LMFDB)
2.31.af_bw33(not in LMFDB)
2.31.n_dg33(not in LMFDB)
2.31.an_dg66(not in LMFDB)
2.31.aj_bo66(not in LMFDB)
2.31.aj_cy66(not in LMFDB)
2.31.f_bw66(not in LMFDB)
2.31.j_bo66(not in LMFDB)
2.31.j_cy66(not in LMFDB)