Equation 5.2.9EFB1A41694DE

\begin{equation} \mathrm{dd}^{\mathrm{c}}u=\frac{\mathrm{i}}{2\pi }\partial \bar\partial u =\frac{\mathrm{i}}{2\pi }\sum _{j,k}u_{j\bar k}\, \mathrm{d}z_ j\wedge \mathrm{d}\bar z_ k, \qquad \Delta u=4\sum _ j u_{j\bar j}. \end{equation}