“…As we explained before, the time-frequency limiting operators in the context of the classical groups where G are the real-line, Z, and ZN were first studied by Landau, Pollak, and Slepian who wrote a series of papers regarding the dimensionality of time-limited signals that are approximately band-limited (or vice versa) [36,37,56,58,60] (see also [57,59] for concise overviews of this body of work). After that, a set of results concerning the number of eigenvalues within the transition region (0, 1) have been established in [13,26,31,38,44,76]. which will be reviewed in detail in the following remarks.…”