ScalingStacks

Proposition 3.6 . [04SU]

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Proposition 3.6.

There exists a proper submanifold Qn⊂(ℂ∗)n+1Q^{n}\subset(\mathbb{C}^{*})^{n+1} such that

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    QnQ^{n} is embedded to (ℂ∗)n+1(\mathbb{C}^{*})^{n+1} symplectically, i.e. so that the restriction of the form (2) to QnQ^{n} is a symplectic form.

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    QnQ^{n} is isotopic to H∘H^{\circ} in (ℂ∗)n+1(\mathbb{C}^{*})^{n+1}.

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    The composition πℱ∘Logt|Qn\pi_{\mathcal{F}}\circ\operatorname{Log}_{t}|_{Q^{n}} is a stratified TnT^{n}-fibration that satisfies to all hypotheses of Theorem 3.

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    the closure Qn¯\bar{Q^{n}} of QnQ^{n} in ℂ​ℙn+1⊃(ℂ∗)n+1{\mathbb{C}}{\mathbb{P}}^{n+1}\supset(\mathbb{C}^{*})^{n+1} is a smooth manifold isotopic to HH.

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    QnQ^{n} is invariant with respect to the action of the symmetric group Sn+2S_{n+2} on (ℂ∗)n+1(\mathbb{C}^{*})^{n+1} (see above).

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    For a sufficiently large M>0M>0

    Qn∩(ℂ∗)−Mn+1=Qn−1×C−M∗,Q^{n}\cap(\mathbb{C}^{*})^{n+1}_{-M}=Q^{n-1}\times\\ C^{*}_{-M},

    where (ℂ∗)−Mn+1={(z1,…,zn+1)∈(ℂ∗)n+1​|log|​zn+1|<−M}(\mathbb{C}^{*})^{n+1}_{-M}=\{(z_{1},\dots,z_{n+1})\in(\mathbb{C}^{*})^{n+1}\ |\ \log|z_{n+1}|<-M\} and ℂ−M∗={z∈ℂ∗​|log|​z|<−M}\mathbb{C}^{*}_{-M}=\{z\in\mathbb{C}^{*}\ |\ \log|z|<-M\}. In particular, the intersection Qn∩(ℂ∗)−Mn+1Q^{n}\cap(\mathbb{C}^{*})^{n+1}_{-M} is invariant under a translation zn+1↦c​zn+1z_{n+1}\mapsto cz_{n+1}, 0<c<10<c<1.

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