We are working with the following signal spaces:
ContSignals = [Reals ® Complex]
DiscSignals = [Integers ® Complex]
ContPeriodicp Ì [Reals ® Complex]
DiscPeriodicp Ì [Integers ® Complex]
where the last two sets contain only periodic signals with period p. The range is generalized to Complex so that we can include complex exponential signals.