|ODELJENJE ZA MATEMATIKU
MATEMATIČKOG INSTITUTA SANU
PROGRAM ZA MART 2017.
PETAK, 17.03.2017. u 14:15, Sala 301f, MI SANU, Kneza Mihaila 36
Hans G. Feichtinger, University of Vienna, Austria
FOURIER STANDARD SPACES: A NEW FAMILY OF FUNCTION SPACES
Classical Harmonic Analysis is focusing very much on the Lebesgue spaces $L^1,L^2,L^\infty$, because they appear at first sight as natural domains for convolution or the Fourier transform. As it has turned out a variant of distribution theory, arising from problems in time-frequency analysis, gives rise the a description of the Fourier transform as an automorphism of the Banach Gelfand Triple (or rigged Hilbert space) $(S_0,L^2,S_0')(R^d)$, i.e. the Plancherel theorem restricts well to the space of test functions $S_0(R^d)$ but also extends well to the distibutions in $S_0'(R^d)$, including Dirac measures, Dirac combs, or pure frequencies.
Fourier standard spaces is a family of Banach spaces between $S_0(R^d)$ and $S_0'(R^d)$, with some extra properties, essentially allowing smoothing (by convolution) and localization (by pointwise multiplication). It is the purpose of this talk to indicate the richness of this family of Fourier standard spaces, among them Wiener amalgam spaces or modulation spaces, and to present a few general claims which can be made for the Banach spaces in this family. Of course, the classical $L^p$-spaces belong to this family, however without playing a significant role there.}