Global L2-boundedness theorems for a class of Fourier integral operators

The local $L^2$-mapping property of Fourier integral operators has been established in H"ormander \cite{H} and in Eskin \cite{E}. In this paper, we treat the global $L^2$-boundedness for a class of operators that appears naturally in many problems. As a consequence, we will improve known global results for several classes of pseudo-differential and Fourier integral operators, as well as extend previous results of Asada and Fujiwara \cite{AF} or Kumano-go \cite{Ku}. As an application, we show a global smoothing estimate to generalized Schr"odinger equations which extends the results of Ben-Artzi and Devinatz \cite{BD}, Walther \cite{Wa}, and \cite{Wa2}.