Multipliers with closed range on commutative semisimple Banach algebras
Let A be a commutative semisimple Banach algebra, Δ(A) its Gelfand spectrum, T a multiplier on A and T̂ its Gelfand transform. We study the following problems. (a) When is δ(T) = inf{|T̂(f)|: f ∈ Δ(A), T̂(f) ≠ 0} > 0? (b) When is the range T(A) of T closed in A and does it have a bounded approximate identity? (c) How to characterize the idempotent multipliers in terms of subsets of Δ(A)?
Multiresolution analysis and Haar wavelets on the Laguerre hypergroup.
Multiresolution analysis and Radon measures on a locally compact Abelian group
A multiresolution analysis is defined in a class of locally compact abelian groups . It is shown that the spaces of integrable functions and the complex Radon measures admit a simple characterization in terms of this multiresolution analysis.