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Proposition 12.14.13F8EA88FD522E

Proposition 12.14.13.F8EA88FD522E For every $n\geq 3$ there are smooth balanced metrics $b_\rho $, $0<\rho <1$, with

\[ \int _ Xh\wedge b_\rho ^ m=1,\qquad b_\rho ^ m\rightharpoonup [Z],\qquad \int _ X\theta \wedge b_\rho ^ m\longrightarrow 0, \qquad D_\mu (b_\rho )\longrightarrow 0 \]

as $\rho \downarrow 0$.

Proof. Choose a nonzero smooth function $f_\rho \geq 0$ on $B$, supported in $\{ x<\rho \} $ and normalized by $\int _ Bf_\rho \omega ^ m=1$. The form

F8E2395BD557 12.14.14
\begin{equation} \Gamma _\rho =\frac{f_\rho \omega ^ m+\rho h^ m}{1+n\rho } \end{equation}

is smooth, strictly positive and closed: the first summand has top degree on the base, and $h$ is Kähler. The positive-root construction in the proof of theorem 11.6.1 gives a unique smooth metric $b_\rho $ with $b_\rho ^ m=\Gamma _\rho $, and $b_\rho $ is balanced because $\Gamma _\rho $ is closed. Since $\int _ Xh^{m+1}=n$, its $h$-trace is one.

Put $C_\theta =\int _ X\theta \wedge h^ m$. Since $a<\rho /t$ on the support of $f_\rho $,

\[ 0\leq \int _ X\theta \wedge \Gamma _\rho \leq \frac{\rho /t+\rho C_\theta }{1+n\rho }\longrightarrow 0. \]

The lower bound in the proof of theorem 12.14.6 gives $D_\mu (b_\rho )\leq n^{-1/n}\int _ X\theta \wedge \Gamma _\rho $, so the determinant integrals also tend to zero. The probability measures $f_\rho \omega ^ m$ converge to the Dirac mass at $p$ because their supports shrink to that point. Fiber integration, as in the preceding proof, gives the current limit $[Z]$, while the term $\rho h^ m$ tends to zero. $\square$

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