I am reading a book on Schroedinger's equation and it says that
"The relation between $\psi(x, 0)$ and $\phi(p)$ [where the latter is the amplitude in the $\psi(x,t)$ integral] is obtained by noting that [the Schroedinger equation] is a Fourier integral and thus can be inverted."
May I ask what the bold bit means? Thanks.