IV.
חᛯƔǒᙸƨȪȸȞȳ᩿Ʒ٭࢟§ 1.
ˮႻ፭Ʒᐯࠁӷԡ᫆ᲴˮႻ፭
R
Ʒᐯࠁӷ፭ƸR
×= R\{ 0 }
ƴǑǔNjƷƠƔƳƍŵᚰଢᲴ
α : R → R
ƕᐯࠁӷưƋǔƱƢǔŵα(1) = 1
ƱƠƯNjǑƍŵƢǔƱŴžn
̿ſǛ ᎋƑǔƜƱƴǑƬƯŴα(λ) = λ, ∀ λ ∈ Q
ƕ ЎƔǔŵஇࢸƴŴໜЗƷಊᨂǛᎋƑǔƜƱ ƴǑƬƯŴα = id
ƱƳǔƜƱƕࢼƏŵഏƴŴ
P SL
2( R )
Ʒᐯࠁӷ፭ƴƭƍƯᎋƑ ǑƏŵˮႻ፭R
ǑǓᢕƔƴᙐᩃƳನᡯǛƠƯ ƍǔŵƠƔƠŴƦƷɶƴಮŷƳžR
ƷſᲷ žɟࢲૠᢿЎ፭ſƕλƬƯƍǔŵ̊ƑƹŴЭׅᙸƨׅ᠃፭
cos(t) sin(t)
− sin(t) cos(t)
| t ∈ R
ƕƦƷˊᘙႎƳ̊ưƋǔŵ
2
ቇҥƳ፼բ᫆ƩƕŴ
P SL
2( R )
Ʒ ɶ࣎Ƹᐯଢ ưƋǔŵƜǕƴǑǓŴγ ∈ P SL
2( R )
ƴݣƠ ƯܭLJǔ ϋᢿᐯࠁӷP SL
2( R ) g → γ · g · γ
−1∈ P SL
2( R )
ǛᎋƑǔƜƱƴǑƬƯŴҥݧ ƳแӷP SL
2( R ) → Aut(P SL
2( R ))
ᲢƨƩƠŴž
Aut( − )
ſƸˮႻ፭ƷᐯࠁӷᲣƕ ưƖǔŵɟ૾ưŴ1 0 0 − 1
ưσࢫƢǔƜ ƱƴǑǔ
ι ∈ Aut(P SL
2( R ))
NjƋǔŵƜƷ ᐯࠁӷι
ƸŴɥҞ᩿Ʒz → z
−1 ƱƍƏ ӒദЩᐯࠁӷ Ჷ ᙐእσࢫ ƴݣࣖƠƯƍ ǔŵƪǐƬƱᩊƠƍܭྸƩƕŴɟࢲૠᢿЎ፭ ሁǛᎋƑǔƜƱƴǑƬƯഏƷǑƏƳƜƱƕ ᚰଢưƖǔŵܭྸᲴɥƷแӷ
P SL
2( R ) → Aut(P SL
2( R ))
ƷƷਦૠƸ2
ưƋǓŴι
ƷƴǑƬƯՠAut(P SL
2( R ))/P SL
2( R )
ƸဃƞǕǔŵ3
§ 2.
ɥҞ᩿Ʒᐯࠁӷ፭ɥҞ᩿
H
ƷᛅƴǖƏŵȪȸȞȳ᩿H
Ʒ ɦᢿˮႻᆰ᧓ ǛT
ƱƘŵኒᲴᢿЎ፭
Aut(H ) ⊆ Aut(T )
ƴƭƍƯᲴ(i) Aut(T )
ϋƷAut(H )
Ʒ ɶ࣎҄ᢿЎ፭Z
Ƹ ᐯଢ ưƋǔŵ(ii) Aut(T )
ϋƷAut(H )
Ʒ ദᙹ҄ᢿЎ፭N
ƸŴAut(H )
Ʊžι : z → z
−1ſưဃƞǕ ǔŵཎƴŴ[N : Aut(H )] = 2
ŵᚰଢᲴ
(i) α ∈ Z
ƱƢǔŵα
Ƹ§ 1
Ʒׅ᠃፭ Ʊӧ੭Ƣǔŵɟ૾ŴƜƷׅ᠃፭ƷɟƷɧ ѣໜƸҾໜưƋǔŵࢼƬƯα
ƸҾໜǛܭ ƢǔŵഏƴAut(H ) ∼ = P SL
2( R )
ƕH
ƴ ਖ਼ᆆႎ ƴ˺ဇƢǔƜƱǛ࣬ƍЈƦƏŵα
ƕAut(H )
ƷƢǂƯƷΨƱӧ੭ƢǔƨNJŴƜǕư
α
ƕH
ƷƢǂƯƷໜǛܭƢǔƜƱƕ ЎƔǔŵ(ii) α ∈ N
ƱƢǔŵܾତƴᄩᛐưƖǔǑƏ ƴŴˮႻ፭Aut(H ) ∼ = P SL
2( R )
ƷˮႻǛŴ4
H
ǁƷ˺ဇƔǒဃƣǔNjƷƱᙸǔƜƱƕư ƖǔŵࢼƬƯŴα
ưσࢫƢǔƜƱƴǑƬƯ ˮႻ፭Aut(H )
Ʒ ᐯࠁӷ ƕܭLJǔŵ§ 1
Ʒ ܭྸǑǓŴဃơƏǔAut(H )
ƷᐯࠁӷƕŴ(ii)
ƴƔǕƨNjƷƴᨂǔƜƱƕЎƔǔŵLJ ƨ(i)
ǑǓžσࢫſƢǔƜƱƴǑƬƯڂǘǕ ǔα
ƕƳƍƜƱƕЎƔǔŵחᛯႎƳᇌئ ƔǒLjǔƱŴƜƷኒƷॖ፯ Ƹ ഏƷᚐƴƋǔᲴኒƷ
(ii)
ƴǑǓŴH
Ʒ ദЩ ನᡯ ǛŴƲƜƔƷ ӋᎋȢȇȫC
ƴǑƬƯܭ፯ƞǕǔNjƷưƸƳƘŴɦᢿˮႻᆰ᧓
T
Ʒᐯ ࠁӷႻϙ፭Aut(T )
ϋƷžཎКƳᢿЎ፭ſA
def= Aut(H ) ⊆ Aut(T )
ƷཎܭƴǑǔNjƷƱᙸǔƜƱƕưƖǔŵƦƏ ƢǔƱᐯࠁӷႻϙ
T →
∼T
ƕžᲢӒᲣദЩſ ƱƸŴžƜƷᢿЎ፭A
Ǜ̬ƭſƱƍƏவˑ ưܭ፯ƢǔƱŴᲢኒƷ(ii)
ƴǑǓᲣƜǕƸ୍ᡫƷܭ፯ Ʊ ɟᐲ ƢǔŵƭLJǓŴӋᎋȢȇȫ
C
Ɣǒᚐ્ ƞǕƨƜƱƴƳǔŵ5
§ 3.
ȪȸȞȳ᩿ɥƷࣇЎȪȸȞȳ᩿ƷஜஹƷܭ፯ƴǖƏŵȪȸȞ ȳ᩿
X
ƷŴƋǔᨼӳƨƪƷC
ǁƷ؈NJ ᡂLjǛ̅ƏƜƱƴǑƬƯŴC
ϋƷ؈NJᡂLj ƷƷɥƷ ࣇЎf (z ) dz
ᲢƨƩƠ
f (z)
ƸദЩ᧙ૠᲣǛᎋƑǔƜƱƕ ưƖǔŵƜƷǑƏƳࣇЎƨƪƕŴžദЩ ƳᝳǓӳǘƤƷӷƨƪſ
z
2= h
21(z
1)
Ʊɲ ᇌႎưƋǔƱƖŴұƪf
2(z
2)dz
2= (dh
21(z
1)/dz
1) · (f
2◦ h
21)(z
1)dz
1= f
1(z
1)dz
1 ųųųųųųǛƨƢƱƖŴƜǕǒƷžޅႎƳࣇЎƨ ƪſǛŴȪȸȞȳ᩿μ˳ƷɥƷࣇЎ Ʊᙸǔ ƜƱƕưƖǔŵƜƷǑƏƳȪȸȞȳ᩿μ˳
ƷɥƷࣇЎƨƪƸŴᚡӭ
Γ(X, ω
X)
ưᘙƞǕǔ
C
șǯȈȫᆰ᧓ǛƢŵ6
ȪȸȞȳ᩿
X
ƕ dzȳȑǯȈ ưƋǔƱˎܭ ƠǑƏŵƢǔƱŴᆔૠg
ᲷžȉȸȊȄཞƷᆭ ƷૠſƱƍƏᙲƳ ˮႻႎɧ٭ ƕƋǔŵ ഏƷܭྸƸȪȸȞȳ᩿ƷྸᛯƷؕஜႎƳኽ ௐưƋǔŵܭྸᲴ
dim
C(Γ(X, ω
X)) = g
ӞχႎƳᇌئƴᇌƭƱŴžࣇЎſ
θ
ƕƋǔƱŴ ƦǕǛ࢘ ᆢЎ ƠƨƘƳǔŵƜƷئӳŴ᩿ɥƷᛅƳƷưŴؕໜ
p
ǛܭƠƯƓƍƯƦ ƷໜƔǒКƷ˓ॖƷໜx
ǁƷ ᢊᲷžȑǹſγ
ƴඝƬƯᆢЎƢǔƜƱƴƳǔŵ7
ƜƷǑƏƴಮŷƳ
x
Ǎθ
ƴݣƠƯᆢЎǛγ
θ ∈ C
ᚘምƢǔƱŴϙX → V
def= Γ(X, ω
X)
∗= Hom
C(Γ(X, ω
X), C )
ᲢƨƩƠŴž∗
ſƸӑݣșǯȈȫᆰ᧓ǛᘙƢᲣƕࢽǒǕƦƏƩƕŴNjƏݲƠɠݗƴᎋƑǔ ƱŴƦƏҥኝƳཞඞưƸƳƍƜƱƕЎƔǔŵ
p
Ʊx
ƕൿLJƬƯƍƯNjγ
ƴƸಮŷƳӧᏡࣱƕƋǔŵཎƴŴ
x = p
ƷƱƖᲢƭLJǓŴžơƨȑǹſƷƱƖᲣ
θ
ƷᆢЎƸ࣏ƣƠNj0
ƴ ƳǔƱƸᨂǒƳƍŵƜƷǑƏƳžơƨȑ ǹſγ
ƴඝƬƯᆢЎƠƯࢽǒǕǔΨ∈ V
Ǜ ԗ ƱԠƿŵ8
ԗƨƪƸŴ
V
ϋƷ܇ ų
Λ ⊆ V
ᲢᲷ
Z
2g ƴӷƳNjƷᲣǛܭ፯ƠƯƍƯŴұ ƪՠJ
def= V /Λ
Ƹ ᭗ഏΨƷᙐእȈȸȩǹ ƴ ƳǔŵഏƷኽௐᲷžǢȸșȫƷܭྸſƸŴȪ ȸȞȳ᩿ƷྸᛯƴƓƚǔᙲƳӞχႎኽௐ ưƋǔŵܭྸᲴ
g ≥ 1
ƷƱƖŴᆢЎƢǔƜƱƴǑƬƯ ࢽǒǕǔݧX → J = V /Λ
Ƹ ദЩƳ؈NJᡂLj ƴƳǔŵ9
§ 4.
ȪȸȞȳ᩿ɥƷʚഏࣇЎ§ 3
ƷǑƏƳžɟഏࣇЎſƩƚưƳƘŴ˓ॖƷn ∈ Z
ƴݣƢǔž᭗ഏƷࣇЎſǛᎋƑǔƜƱ NjӧᏡưƋǔŵƭLJǓŴȪȸȞȳ᩿ƷӲŷƷ ޅႎƳC
ǁƷ؈NJᡂLjǛ̅ƏƜƱƴǑƬ ƯŴC
ϋƷ؈NJᡂLjƷƷɥƷn
ഏࣇЎf (z ) dz
nᲢƨƩƠ
f (z)
ƸദЩ᧙ૠᲣǛᎋƑǔŵƜƷǑ ƏƳn
ഏࣇЎƨƪƕŴžദЩ Ƴ ᝳǓӳǘƤƷ ӷƨƪſz
2= h
21(z
1)
ƴݣƠƯவˑf
2(z
2)dz
2n= (dh
21(z
1)/dz
1)
n· (f
2◦ h
21)(z
1)dz
1n= f
1(z
1)dz
1n ųųųųųųǛƨƢƱƖŴƜǕǒƷžޅႎƳ
n
ഏࣇЎ ƨƪſǛŴȪȸȞȳ᩿μ˳ƷɥƷn
ഏࣇЎ ƱᙸǔƜƱƕưƖǔŵƜƷǑƏƳȪȸȞȳ᩿μ˳ƷɥƷ
n
ഏࣇЎƨƪƸŴᚡӭΓ(X, ω
X⊗n)
ưᘙƞǕǔ
C
șǯȈȫᆰ᧓ǛƢŵ10
ȪȸȞȳ᩿
X
ƕ dzȳȑǯȈ ưƠƔNj ӑႎ ưƋǔƱˎܭƠǑƏŵƜƷӑࣱƷவˑƸŴܱƸ
g ≥ 2
ƱƍƏவˑƱӷ͌ưƋǔƜƱƸŴ ɟॖ҄ܭྸ ǑǓႺƪƴࢼƏŵᲢƭLJǓŴg = 0
ƩƱŴX
Ƹ ྶ᩿ ƴƳǓŴg = 1
ƩƱŴX
Ƹ ɟഏΨᙐእȈȸȩǹ ƴƳǔƨNJŴ୍ᢄᘮᙴ ƸC
ƱദЩƴӷƴƳǔŵᲣƢǔƱŴƍǘǏǔ ȪȸȞȳȷȭȃț ƱƍƏŴ ȪȸȞȳ᩿ƷӞχႎƳྸᛯƴƓƚǔؕஜႎ ƳܭྸǑǓഏƷኽௐƕࢼƏŵ
ܭྸᲴ
(i) n < 0
ƷƱƖŴdim
C(Γ(X, ω
X⊗n)) = 0 (ii) n = 0
ƷƱƖŴdim
C(Γ(X, ω
X⊗n)) = 1 (iii) n = 1
ƷƱƖŴdim
C(Γ(X, ω
X⊗n)) = g (iv) n ≥ 2
ƷƱƖŴųų
dim
C(Γ(X, ω
X⊗n)) = (2n − 1)(g − 1)
ཎƴŴdim
C(Γ(X, ω
X⊗2)) = 3(g − 1)
11
n
ഏࣇЎƷɶưNjŴžʚഏࣇЎſƸཎƴᙲ ưƋǔŵƦǕƸɟᚕưƍƏƱŴʚഏࣇЎƸŴȪȸȞȳ᩿ƷȢǸȥȩǤ
Ʊ݅ƴ᧙̞ƠƯƍǔƔǒưƋǔŵƜƜư ƍƏžȪȸȞȳ᩿ƷȢǸȥȩǤſƱƸŴɦ ᢿˮႻ᩿ǛܭƠƨƱƖŴദЩನᡯ ƕƲ ƷƘǒƍѣƖࢽǔƔŴƱƍƏƜƱưƋǔŵ
̊ƑƹŴ
0 = θ ∈ Γ(X, ω
X⊗2)
ƱƠǑƏŵƢǔ ƱŴθ
ƕ ᩐໜǛਤƨƳƍŴȪȸȞȳ᩿X
Ʒ җЎƴݱƞƍᨼӳU
Ʒໜp ∈ U
Ǜ ؕໜ ƴᢠƿƱŴx ∈ U
ƴݣƠƯŴp
Ɣǒx
ǁƷȑ ǹγ
ƴඝƬƯθ
Ʒ ૾ఌ± √
θ
ǛᆢЎƢǔγ
± √ θ
ƜƱƴǑƬƯŴ
U
ɥƷ ޅႎƳദЩࡈ ƕ ưƖǔŵƜƷǑƏƳࡈǛ ٭࢟ ƢǔƜƱƴ ǑƬƯX
ƷȢǸȥȩǤǛᎋݑƢǔƜƱƕŴ ӞχႎTeichm¨ uller
ྸᛯ ƷЈႆໜưƋǔŵ12
§ 5.
ȪȸȞȳ᩿ɥƷᘍׄᡀ࢟ሁȪȸȞȳ᩿
X
ƷҗЎƴݱƞƍᨼӳU ⊆ X
ɥƴʚഏࣇЎƷ૾ఌƷᆢЎz
def=
γ
± √ θ
ƴǑǔ ࡈ
z = x + iy
ƴƭƍƯᎋƑǔŵLJ ƣŴλ ∈ R
>0 ƴݣƠƯz
λ def= λ · x + iy
ƱƍƏ КƷࡈ ǛᎋƑǔƜƱƕưƖǔŵƜ ƷૼƠƍࡈ
z
λ ƴǑƬƯŴૼƠƍ ദЩನᡯ
ƕൿLJǔŵ࢘ƨǓЭưƸƳƍƕŴƜƷǑƏ ƴ ޅႎ ƴ˺ƬƨૼƠƍദЩನᡯƨƪƸଓ ƘᝳǓӳƏƨNJŴ
X
ƷɦᢿˮႻ᩿T
μ˳ƷɥƷૼƠƍദЩನᡯǛܭ፯ƠƯƍǔŵ
13
ƜƷǑƏƴƠƯưƖǔȪȸȞȳ᩿Ǜ
X
λ ƱƘƱŴ
X
ƱX
λ ƕӷɟƷɦᢿˮႻ᩿Ǜ σஊƠƯƍǔƜƱƴǑƬƯŴᲢᲢӒᲣദЩᲷ ሁᚌưƸƳƍƕᲣલሁᚌ ƳӷႻϙX → X
λƕưƖǔŵƜƷǑƏƴƠƯ˺ƬƨϙƸ
Teichm¨ uller
ϙƱԠƹǕǔNjƷưŴಮŷƳཎКƳࣱឋǛਤƬ ƯƍǔŵƳƓŴ
λ ∈ R
>0 ǛѣƔƢƜƱƴǑƬƯŴ
X
ƷɦᢿˮႻ᩿T
ɥƴദ ЩನᡯƷ ɟࢲૠଈ ƕưƖǔŵഏƴŴɥƷᛅƷǑƏƳ ࡈƨƪ Ǜ̅ƬƯ
C ∈ { Squr, Rect, Para }
ƴݣƠƯŴ
X
ɥƷ ׄᚌŴᧈ૾࢟ŴƋǔƍƸᘍׄᡀ࢟ ƔǒƳǔח
C (X )
Ǜ˺ǔƜƱƕ ưƖǔƜƱƴදႸƠǑƏŵ14
ܭྸᲴ
X
ƱY
ƸӑႎȪȸȞȳ᩿ƱƢǔŵ(i) C ∈ { Squr, Rect }
ƷƱƖŴחӷ͌
C (X ) → C
∼(Y )
ƷӷƱ
ᲢӒᲣദЩƳӷ
X →
∼Y
Ƹ
1
ݣ1
ƴݣࣖƠƯƍǔŵ(ii) C = Para
ƷƱƖŴחӷ͌
C (X ) → C
∼(Y )
ƷӷƱ
ᲢӒᲣ
Teichm¨ uller
ϙX →
∼Y
Ƹ1
ݣ1
ƴݣࣖƠƯƍǔŵ15
ᚰଢƸƦǕDŽƲᩊƠƘƳƍƕɦᚡƷᛯ૨ƴ ᜯǔŵ