ScalingStacks

Proposition 3.4 . [05DN]

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Proposition 3.4.

Let S¯⟂\bar{S}^{\perp} be the orthogonal complement of S¯\bar{S} in ℂn\mathbb{C}^{n}, i.e. ℂn=S¯⊕S¯⟂\mathbb{C}^{n}=\bar{S}\oplus\bar{S}^{\perp}, and gE​(v,w)=0g_{E}(v,w)=0, for any v∈S¯v\in\bar{S} and w∈S¯⟂w\in\bar{S}^{\perp}. Then

  • i)

    (X~,π∗​g0)(\tilde{X},\pi^{*}g_{0}) is isometric to (Tn×S¯⟂,h+hE)(T^{n}\times\bar{S}^{\perp},h+h_{E}), where Tn=S¯/Λ=S~T^{n}=\bar{S}/\Lambda=\tilde{S}, hE=gE|S¯⟂h_{E}=g_{E}|_{\bar{S}^{\perp}}, and hh is the standard flat metric on TnT^{n} induced by gE|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 TnT^{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∈Tnx\in T^{n} and y∈S¯⟂y\in\bar{S}^{\perp}. Furthermore, Tn×{0}T^{n}\times\{0\} is Γ\Gamma-invariant, and S=π⁡(Tn×{0})=(Tn×{0})/ΓS=\pi(T^{n}\times\{0\})=(T^{n}\times\{0\})/\Gamma.

  • iii)
    π∗​ω0|Tn×{y}≡0,andπ∗​Im​e−1​θ0​Ω0|Tn×{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 θ0∈ℝ\theta_{0}\in\mathbb{R}.

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