The structure of L-ideals of measure algebras. II
We prove that if does not contain parallelepipeds of arbitrarily large dimension then for any open, non-empty there exists a constant c > 0 such that for all whose Fourier transform is supported on E. In particular, such functions cannot vanish on any open, non-empty subset of G. Examples of sets which do not contain parallelepipeds of arbitrarily large dimension include all Λ(p) sets.
A reproducing system is a countable collection of functions such that a general function f can be decomposed as , with some control on the analyzing coefficients . Several such systems have been introduced very successfully in mathematics and its applications. We present a unified viewpoint in the study of reproducing systems on locally compact abelian groups G. This approach gives a novel characterization of the Parseval frame generators for a very general class of reproducing systems on L²(G)....
We prove the Paley-Wiener theorem for the Helgason Fourier transform of smooth compactly supported 𝔳-radial functions on a Damek-Ricci space S = NA.