Über Jackson- und Bernstein-Typ Ungleichungen für lineare Approximationsverfahren in Lp (En).
On Fourier multiplier criteria of Marcinkiewicz type
On weighted transplantation and multipliers for Laguerre expansions.
Jacobi and Hankel Multipliers of Type (p,q},1<p<q<oo.
Multiplier criteria of Hörmander type for Jacobi expansions
A characterization of localized Bessel potential spaces and applications to Jacobi and Henkel multipliers
Hankel multipliers and transplantation operators
Connections between Hankel transforms of different order for -functions are examined. Well known are the results of Guy [Guy] and Schindler [Sch]. Further relations result from projection formulae for Bessel functions of different order. Consequences for Hankel multipliers are exhibited and implications for radial Fourier multipliers on Euclidean spaces of different dimensions indicated.
Fractional powers of operators, K-functionals, Ulyanov inequalities
Given an equibounded (₀)-semigroup of linear operators with generator A on a Banach space X, a functional calculus, due to L. Schwartz, is briefly sketched to explain fractional powers of A. Then the (modified) K-functional with respect to , α > 0, is characterized via the associated resolvent R(λ;A). Under the assumption that the resolvent satisfies a Nikolskii type inequality, , for a suitable Banach space Y, an Ulyanov inequality is derived. This will be of interest if one has good control...
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