Formula_1101

\[u(x, t)=(2 \pi)^{-3 / 2} \int_{\mathbb{R}^{3}} C(k, \omega) \tilde{u}(x, \hat{k}) \exp \left(-i k^{2} t\right) d \hat{k}, \omega=\frac{\hat{k}}{k},\]