This refers to the link :
where in the History section it mentions that:
"Many methods were designed to generate such spaces of functions, including the Fourier transform, complex interpolation, real interpolation, as well as other tools (see e.g. fractional derivative)."
May I ask how how Fourier transform can be used to generate such space? As I understand Fourier transform; it is a transformation from one domain to another; how can it be used as a interpolation space? Few comments would be highly appreciated.