1. Department of Mathematics, University of Torino, Via Carlo Alberto 10, 10123, Torino, Italy 2. Departamento de An??lisis Matem??tico, Universidad de Valencia, Doctor Moliner 50, 46100, Burjasot (Valencia), Spain
Abstract:
In this paper we consider a version of the uncertainty principle concerning limitations on the supports of time-frequency representations in the Cohen class. In particular we obtain various classes of kernels with the property that the corresponding representations of non trivial signals cannot be compactly supported. As an application of our results we show that a linear partial differential operator applied to the Wigner distribution of a function f≠0 in the Schwartz class cannot produce a compactly supported function.