RADIATION FIELDS FOR SEMILINEAR WAVE EQUATIONS

We define the radiation fields of solutions to critical semilinear wave equations in R-3 and use them to define the scattering operator. We also prove a support theorem for the radiation fields with radial initial data. This extends the well-known support theorem for the Radon transform to this setting and can also be interpreted as a Paley-Wiener theorem for the distorted nonlinear Fourier transform of radial functions.