ScalingStacks

Proof. [023T]

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Proof.

We will ignore all exponentially small errors coming from identifying tubular neighbourhoods with normal bundles. We compute d​dc​ϕD1dd^{c}\phi_{D_{1}} by the Leibniz rule:

d​dc​x~1n+2n=2​(n+2)n2​x~1n+2n−2​−14​π​d22​d​log⁡ξ′∧d​log⁡ξ′¯,dd^{c}\tilde{x}_{1}^{\frac{n+2}{n}}=\frac{2(n+2)}{n^{2}}\tilde{x}_{1}^{\frac{n+2}{n}-2}\frac{\sqrt{-1}}{4\pi d_{2}^{2}}d\log\xi^{\prime}\wedge d\overline{\log\xi^{\prime}},
d​dc​(x~1n−2n⁡(n−1)​ϕT​Y)=n−2n⁡(n−1)​(n−2n⁡(n−1)−1)​x~1n−2n⁡(n−1)−2​ϕT​Y​−14​π​d22​d​log⁡ξ′∧d​log⁡ξ′¯+n−2n⁡(n−1)​x~1n−2n⁡(n−1)−1​(d​x~1∧dc​ϕT​Y+d​ϕT​Y∧dc​x~1)+x~1n−2n⁡(n−1)​d​dc​ϕT​Y.\begin{split}&dd^{c}(\tilde{x}_{1}^{\frac{n-2}{n(n-1)}}\phi_{TY})=\frac{n-2}{n(n-1)}(\frac{n-2}{n(n-1)}-1)\tilde{x}_{1}^{\frac{n-2}{n(n-1)}-2}\phi_{TY}\frac{\sqrt{-1}}{4\pi d_{2}^{2}}d\log\xi^{\prime}\wedge d\overline{\log\xi^{\prime}}\\ &+\frac{n-2}{n(n-1)}\tilde{x}_{1}^{\frac{n-2}{n(n-1)}-1}(d\tilde{x}_{1}\wedge d^{c}\phi_{TY}+d\phi_{TY}\wedge d^{c}\tilde{x}_{1})+\tilde{x}_{1}^{\frac{n-2}{n(n-1)}}dd^{c}\phi_{TY}.\end{split}

and similarly with d​dc​(x~1n+2n−k​nn−1​x2k​nn−1)dd^{c}(\tilde{x}_{1}^{\frac{n+2}{n}-\frac{kn}{n-1}}x_{2}^{\frac{kn}{n-1}}).

Comparing v0​d​dc​x~1n+2nv_{0}dd^{c}\tilde{x}_{1}^{\frac{n+2}{n}} and the term 2​(n+2)​v0n2​d22​x1′−n−2n​−14​π​d​log⁡ξ′∧d​log⁡ξ′¯\frac{2(n+2)v_{0}}{n^{2}d_{2}^{2}}x_{1}^{\prime-\frac{n-2}{n}}\frac{\sqrt{-1}}{4\pi}d\log\xi^{\prime}\wedge d\overline{\log\xi^{\prime}}, the deviation is of order O⁡(|x2|+|x1−x1′|x1′)O(\frac{|x_{2}|+|x_{1}-x_{1}^{\prime}|}{x_{1}^{\prime}}). Notice for n≥3n\geq 3, we have n2​(n−1)<1\frac{n}{2(n-1)}<1 and so |x2|x1′≤(x2x1)n2​(n−1)\frac{|x_{2}|}{x_{1}^{\prime}}\leq\left(\frac{x_{2}}{x_{1}}\right)^{\frac{n}{2(n-1)}}. For |x1−x1′|≤x1′n−22​(n−1)|x_{1}-x_{1}^{\prime}|\leq x_{1}^{\prime\frac{n-2}{2(n-1)}}, the error O⁡(|x1−x1′|x1′)=O⁡(x1−n2​(n−1))O(\frac{|x_{1}-x_{1}^{\prime}|}{x_{1}^{\prime}})=O(x_{1}^{-\frac{n}{2(n-1)}}), which is absorbed into O⁡((x2x1)n2​(n−1))O((\frac{x_{2}}{x_{1}})^{\frac{n}{2(n-1)}}).

Using the lemmas, we can estimate the terms appearing in d​dc​(x~1n−2n⁡(n−1)​ϕT​Y)dd^{c}(\tilde{x}_{1}^{\frac{n-2}{n(n-1)}}\phi_{TY}) in the local Ck,αC^{k,\alpha}-norms:

‖ϕT​Y​x1n−2n⁡(n−1)−2​d​log⁡ξ′∧d​log⁡ξ′¯‖k,α,l​o​c=O⁡(x2n(n−1)​x1n−2n⁡(n−1)−2​x1n−2n)=O⁡((x2x1)nn−1).\left\lVert\phi_{TY}x_{1}^{\frac{n-2}{n(n-1)}-2}d\log\xi^{\prime}\wedge d\overline{\log\xi^{\prime}}\right\rVert_{k,\alpha,loc}=O(x_{2}^{\frac{n}{(n-1)}}x_{1}^{\frac{n-2}{n(n-1)}-2}x_{1}^{\frac{n-2}{n}})=O((\frac{x_{2}}{x_{1}})^{\frac{n}{n-1}}).

The cross terms have order

‖x1n−2n⁡(n−1)−1​d​log⁡ξ′∧dc​ϕT​Y‖k,α,l​o​c=O⁡(x1n−2n⁡(n−1)−1​x1n−22​n​x1−n−22​n​(n−1)​x2n2​(n−1))=O⁡((x2x1)n2​(n−1)).\left\lVert x_{1}^{\frac{n-2}{n(n-1)}-1}d\log\xi^{\prime}\wedge d^{c}\phi_{TY}\right\rVert_{k,\alpha,loc}=O(x_{1}^{\frac{n-2}{n(n-1)}-1}x_{1}^{\frac{n-2}{2n}}x_{1}^{-\frac{n-2}{2n(n-1)}}x_{2}^{\frac{n}{2(n-1)}})=O((\frac{x_{2}}{x_{1}})^{\frac{n}{2(n-1)}}).

So does its complex conjugate. The last error comes from the deviation between x~1n−2n⁡(n−1)​d​dc​ϕT​Y\tilde{x}_{1}^{\frac{n-2}{n(n-1)}}dd^{c}\phi_{TY} from x1′n−2n⁡(n−1)​d​dc​ϕT​Yx_{1}^{\prime\frac{n-2}{n(n-1)}}dd^{c}\phi_{TY}. This error is again of order O⁡(|x2|+|x1−x1′|x1′)O(\frac{|x_{2}|+|x_{1}-x_{1}^{\prime}|}{x_{1}^{\prime}}).

The remainder terms have leading order contribution d​dc​(x~1n+2n−2​nn−1​x22​nn−1).dd^{c}(\tilde{x}_{1}^{\frac{n+2}{n}-\frac{2n}{n-1}}x_{2}^{\frac{2n}{n-1}}). Its main contribution is x~1n+2n−2​nn−1​d​dc​x22​nn−1\tilde{x}_{1}^{\frac{n+2}{n}-\frac{2n}{n-1}}dd^{c}x_{2}^{\frac{2n}{n-1}}, which has magnitude O⁡((x2x1)nn−1)O((\frac{x_{2}}{x_{1}})^{\frac{n}{n-1}}). Combining all the errors, the deviation between d​dc​ϕD1dd^{c}\phi_{D_{1}} and the local product metric (32) has magnitude bounded by O⁡((x2x1)n2​(n−1)).O((\frac{x_{2}}{x_{1}})^{\frac{n}{2(n-1)}}). ∎

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