Pome

Lemma 13.15.3357B2DE7779E

Lemma 13.15.3.357B2DE7779E Let $u\in \mathrm{PSH}(X,\omega )$ be nonpositive. For $t\geq 0$ and every Borel set $E\subset X$,

F3E7262939D2 13.15.4
\begin{equation} \mu _ u(\{ u\geq -t\} )\leq C_\omega (1+t)^{r_ n}, \qquad \mu _ u(E\cap \{ u\geq -t\} )\leq (1+t)^ n\operatorname {Cap}_\omega (E). \end{equation}

Proof. Put $v_ t=\max (u,-t-1)+t+1$. It is $\omega $-plurisubharmonic and takes values in $[0,t+1]$, and by plurifine locality its Monge–Ampère measure equals $\mu _ u$ on $\{ u\geq -t\} \subset \{ u>-t-1\} $. The first estimate therefore follows from proposition 13.15.2, after enlarging the constant. For the second, $v_ t/(1+t)$ is a test function for the capacity, and positivity gives

\[ (\omega +\mathrm{dd}^{\mathrm{c}}v_ t)^ n \leq (1+t)^ n\bigl (\omega +\mathrm{dd}^{\mathrm{c}}(v_ t/(1+t))\bigr )^ n. \]

Restricting this inequality to $E\cap \{ u\geq -t\} $ proves the capacity bound. $\square$

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