Holomorphic Sobolev spaces, Hermite and special Hermite semigroups and a Paley–Wiener theorem for the windowed Fourier transform

The images of Hermite and Laguerre–Sobolev spaces under the Hermite and special Hermite semigroups (respectively) are characterized. These are used to characterize the image of Schwartz class of rapidly decreasing functions f on R n and C n under these semigroups. The image of the space of tempered distributions is also considered and a Paley–Wiener theorem for the windowed (short-time) Fourier transform is proved.