Example 1

(3,4)-Curve

Vector of Riemann constants

Thecurveisdefinedbytheequation​​-
3
y
+y(4
2
x
+5x+11)+
4
x
+3
3
x
+7
2
x
+16x+9=0
Periodsarepreviouslycomputed

Periods


Theta-function definition


Characteristics of order 2


Vanishing odd θ-functions w.r.t.
v
1

InvMωA=Inverse[MωA];​​Acc=5;​​(*Compute
∂
v
1
θ[ε](0;τ)withoddcharacteristics*)​​DOddThetaList=TableDThetaCh
1
2
OddChars[[i]],{V1,V2,V3},τA,Acc,V1/.{V1->0,V2->0,V3->0},{i,1,Length[OddChars]};
∂
v
1
θ[ε](0;τ)≠0foralloddcharacteristics.
Herev=
-1
ω
uarenormalizedcoordinatesonJac()
[K] can not be singled out
DOddThetaList//TableForm
Out[]//TableForm=
-0.222968154117498+0.841731534511779
-0.436925131409659+0.752983537453354
0.223487042164506-0.841392488745694
0.437531782226707-0.752856369756969
0.100998947075545+0.735765867423013
0.591682074590233-0.448847993850597
-0.100929189141844-0.736002191966474
-0.591799854969513+0.449064426845801
0.058830051865581+0.058830051865580
0.355980169713770+0.355980169713768
-0.059304695492673-0.059304695492672
-0.355952336871781-0.355952336871779
-1.855765566223786-2.446096505872586
-3.041875842908558+0.417427010569896
-1.476774057918523-2.448465066750659
-2.775563202832327+0.687089301563201
1.579833231367252+1.579833231367253
1.844747749497915+1.844747749497916
-2.594274892909448-2.594274892909445
-2.328098906025485-2.328098906025485
2.607311589208755-0.266590334653883
0.642137005526967-1.642904368043174
-0.642137005526974-1.642904368043170
-2.607311589208756-0.266590334653879
0.233774661819535+1.758186654853675
2.527584807704605-0.541037054651932
-1.404701387334451-2.169843327769597
1.408529354880911-1.077922057596545

Vanishing odd θ-functions w.r.t.
u
1

Criteria:θ[K]vanishestotheweigthedorder=
1
24
(
2
n
-1)(
2
s
-1).
 = 5 on (3, 4)-curve
In[]:=
1
24
(
2
n
-1)(
2
s
-1)/.{n->3,s->4}
Out[]=
5
InvMωA=Inverse[MωA];​​Acc=5;​​(*Compute
∂
u
1
θ[ε](0;τ)withoddcharacteristics*)​​DDUOddThetaList=TableDThetaCh
1
2
OddChars[[i]],InvMωA.{U1,U2,U5},τA,Acc,U1/.{U1->0,U2->0,U5->0},{i,1,Length[OddChars]};
∂
u
1
θ[K](0;τ)=0,and
∂
u
1
θ[ε](0;τ)≠0foralloddcharacteristicsbut[K]
In[]:=
DDUOddThetaList//TableForm
Out[]//TableForm=
0.418965754002278-0.583770339901214
-0.236925300597791-0.925098139250597
0.821674654214512-0.486611680839797
0.116534440259777-0.709041491739669
-1.279823483502825+0.951473623512473
0.232178412600831+1.577765315212444
-0.906700499702771+0.773818479630065
0.093961777491176+1.188306366198945
0.725223280391731-0.725223280391731
-1.375624726523541+1.375624726523541
1.002669199078804-1.002669199078804
-1.008305308768233+1.008305308768232
0.817701755096032-1.033085932522258
0.152299612418370-1.308704524451464
0.159394540305415-0.550830270157562
0.276786858977162-0.502204779645302
-0.180208043351292+0.180208043351291
-1.×
-15
10
-2.×
-15
10

1.086273635588643-1.086273635588645
0.474982513395378-0.474982513395376
-0.373875966221430+0.903329443294439
0.362998710993960+1.549444189933544
0.362998710993960-1.549444189933545
-0.373875966221430-0.903329443294440
0.300457080033064+0.369108094868992
-0.633866501485503+1.370846135070406
0.521123296504262-1.417545899639046
-0.473454075619601+0.048543598125823
(*ChoosethenumberfromOddCharsofcharacteristic[K],suchthat​​
∂
u
1
θ[K](0;τ)=0*)​​DDUOddThetaVanishNumList={};​​Do[If[Chop[DDUOddThetaList[[i]]]==0,DDUOddThetaVanishNumList=Append[DDUOddThetaVanishNumList,i]],{i,1,Length[OddChars]}]​​DDUOddThetaVanishNumList//Length​​KNum=DDUOddThetaVanishNumList[[1]];​​
1
2
OddChars[[KNum]]//MatrixForm
Out[]=
1
Out[]//MatrixForm=
1
2
0
1
2
0
1
2
1
2
(*Verification:theorderofvanishingofθ[K]is5*)​​DThetaCh
1
2
OddChars[[KNum]],InvMωA.{U1,U2,U5},τA,Acc,{U1,3}/.{U1->0,U2->0,U5->0}​​DThetaCh
1
2
OddChars[[KNum]],InvMωA.{U1,U2,U5},τA,Acc,{U1,5}/.{U1->0,U2->0,U5->0}
Out[]=
0.×
-15
10
-0.×
-15
10

Out[]=
-26.0300270293482+26.0300270293482
Example 2

Hyperelliptic genus 4

Vector of Riemann constants

Thecurveisdefinedbytheequation​​-
2
y
+(x+18+2)(x+16-5)(x+11-3)(x+10+)(x+4-2)(x+3-3)(x-3-3)(x-7+2)(x-13+)=0
Periodsarepreviouslycomputed

Periods


Theta-function definition


Characteristics of order 2


Vanishing even θ-functions w.r.t
v
1

There are 10 branch points, with indices
S={1,2,3,4,5,6,7,8,9,0}
,
where 0 stands for ∞
Every characteristic is assigned by a partition
ℐ

⋃


of
S
, where

is called multiplicity
Half-integer characteristics consists of

ℐ

#
0
{
i
1
,
i
2
,
i
3
,
i
4
}

9
4
=126
evennonsingular
θ[ε](0;τ)≠0
1
{
i
1
,
i
2
,
i
3
}

10
3
=120
oddnonsingular
θ[ε](0;τ)=0,​​
∂
v
θ[ε](0;τ)≠0
2
{
i
1
}
10
evensingular
θ[ε](0;τ)=0,​​
2
∂
v
θ[ε](0;τ)≠0
[K] is among even singular characteristics,
but can not be singled out by differentiating w.r.t. normalized coordinates v
◼
  • [K]
  • CITE THIS NOTEBOOK

    Vector of Riemann constants​
    by Julia Bernatska​
    Wolfram Community, STAFF PICKS, October 11, 2024
    ​https://community.wolfram.com/groups/-/m/t/3296279