Pome

Theorem 16.28.4609FE648CAD9A

Theorem 16.28.46.09FE648CAD9A Let $a\in K$, $\tau >0$ and $\Psi \in \mathcal L_\tau \cap C(\mathbb C^ n)$, and put $q=\Psi |_ K$. Suppose that, for some $R,c>0$,

\[ \mathrm{dd}^{\mathrm{c}}\Psi \geq c\omega _0\quad \text{on }B(a,R), \qquad \omega _0=\mathrm{dd}^{\mathrm{c}}\lVert z\rVert ^2. \]

For $0<r<R$ and $\delta \geq \tau $,

8D81382EAE2C 16.28.47
\begin{equation} F_{\delta ,K,q}(a)-\Psi (a) \geq cr^2\bigl (1+h_{K_ r,B(a,R)}^*(a)\bigr ). \end{equation}

Regular contact at $a$, that is, $F_{\delta ,K,q}(a)=q(a)$, holds for some $\delta \geq \tau $ if and only if $K$ is locally pluriregular at $a$. In that case it holds for every $\delta \geq \tau $.

Proof. Set $B=B(a,R)$ and $E=K_ r$. For a competitor $u$ for $h_{E,B}$, the function

\[ H_ u(z)=\Psi (z)-c\lVert z-a\rVert ^2+cr^2(u(z)+1) \]

is plurisubharmonic on $B$, because the assumption on $\mathrm{dd}^{\mathrm{c}}\Psi $ makes $\Psi -c\lVert z-a\rVert ^2$ plurisubharmonic there. Since $u\leq 0$, we have $H_ u\leq \Psi $ where $\lVert z-a\rVert \geq r$. Define $W=\max (\Psi ,H_ u)$ on $B$ and $W=\Psi $ outside $B$. The two definitions agree near $\partial B$, so $W$ is plurisubharmonic on $\mathbb C^ n$, and it belongs to $\mathcal L_\tau $ because it equals $\Psi $ outside $B$. On $E$, the equality $u=-1$ gives $H_ u\leq \Psi $, and on $K\setminus E$ the distance bound gives the same inequality. Thus $W=q$ on $K$, so $W$ is a competitor for $F_{\delta ,K,q}$ for each $\delta \geq \tau $. Since $W\geq H_ u$ near $a$, taking the supremum over $u$, regularizing, and using the continuity of $\Psi $, we obtain (16.28.47).

The function $\Psi $ itself is a competitor, so raw contact holds for every $\delta \geq \tau $. If regular contact holds for one such $\delta $, the left-hand side of the estimate vanishes, so $h_{K_ r,B(a,R)}^*(a)=-1$ for all $0<r<R$. By lemma 16.28.43, every $K_ r$ with $r<R$ is then non-pluripolar and satisfies $V_{K_ r}^*(a)=0$; for $r\geq R$ this follows by monotonicity. Conversely, local pluriregularity and lemma 16.28.45 give regular contact at $a$ for every $\delta \geq \tau $. $\square$

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