Proposition 3.4 . [05DN] Original official author HTML, exact retained edition. Historical TeX conversion verdicts remain unchanged. Cited-edition alignment and mathematical self-containment are not assessed.
Source coverage notes 1 original structured objects have an unresolved mathematical role; their permanent tags identify source occurrences only. Complete original source context · Original author HTML
Proposition 3.4 .
Let S ¯ ⟂ \bar{S}^{\perp} be the orthogonal complement of
S ¯ \bar{S} in ℂ n \mathbb{C}^{n} , i.e. ℂ n = S ¯ ⊕ S ¯ ⟂ \mathbb{C}^{n}=\bar{S}\oplus\bar{S}^{\perp} ,
and g E ( v , w ) = 0 g_{E}(v,w)=0 , for any v ∈ S ¯ v\in\bar{S} and w ∈ S ¯ ⟂ w\in\bar{S}^{\perp} . Then
i)
( X ~ , π ∗ g 0 ) (\tilde{X},\pi^{*}g_{0}) is isometric to ( T n × S ¯ ⟂ , h + h E ) (T^{n}\times\bar{S}^{\perp},h+h_{E}) , where T n = S ¯ / Λ = S ~ T^{n}=\bar{S}/\Lambda=\tilde{S} ,
h E = g E | S ¯ ⟂ h_{E}=g_{E}|_{\bar{S}^{\perp}} , and h h is the standard flat metric on T n T^{n} induced by g E | S ¯ g_{E}|_{\bar{S}} .
ii)
The action of Γ \Gamma on X ~ \tilde{X} is a product
action, i.e. there are Γ \Gamma -actions on T n T^{n} and S ¯ ⟂ \bar{S}^{\perp} such that γ ⋅ ( x , y ) = ( γ ⋅ x , γ ⋅ y ) \gamma\cdot(x,y)=(\gamma\cdot x,\gamma\cdot y) for any γ ∈ Γ \gamma\in\Gamma , x ∈ T n x\in T^{n} and y ∈ S ¯ ⟂ y\in\bar{S}^{\perp} .
Furthermore,
T n × { 0 } T^{n}\times\{0\} is Γ \Gamma -invariant,
and S = π ( T n × { 0 } ) = ( T n × { 0 } ) / Γ S=\pi(T^{n}\times\{0\})=(T^{n}\times\{0\})/\Gamma .
iii)
π ∗ ω 0 | T n × { y } ≡ 0 , and π ∗ Im e − 1 θ 0 Ω 0 | T n × { y } ≡ 0 , \pi^{*}\omega_{0}|_{T^{n}\times\{y\}}\equiv 0,\ \ {\rm and}\ \ \pi^{*}{\rm Im}e^{\sqrt{-1}\theta_{0}}\Omega_{0}|_{T^{n}\times\{y\}}\equiv 0,
for any y ∈ S ¯ ⟂ y\in\bar{S}^{\perp} , and a constant
θ 0 ∈ ℝ \theta_{0}\in\mathbb{R} .