Article ID Journal Published Year Pages File Type
4614070 Journal of Mathematical Analysis and Applications 2017 19 Pages PDF
Abstract

In this paper we deal with Banach spaces of analytic functions X   defined on the unit disk satisfying that Rtf∈XRtf∈X for any t>0t>0 and f∈Xf∈X, where Rtf(z)=f(eitz)Rtf(z)=f(eitz). We study the space of functions in X   such that ‖Pr(Df)‖X=O(ω(1−r)1−r), r→1−r→1− where Df(z)=∑n=0∞(n+1)anzn and ω is a continuous and non-decreasing weight satisfying certain mild assumptions. The space under consideration is shown to coincide with the subspace of functions in X   satisfying any of the following conditions: (a) ‖Rtf−f‖X=O(ω(t))‖Rtf−f‖X=O(ω(t)), (b) ‖Prf−f‖X=O(ω(1−r))‖Prf−f‖X=O(ω(1−r)), (c) ‖Δnf‖X=O(ω(2−n))‖Δnf‖X=O(ω(2−n)), or (d) ‖f−snf‖X=O(ω(n−1))‖f−snf‖X=O(ω(n−1)), where Prf(z)=f(rz)Prf(z)=f(rz), snf(z)=∑k=0nakzk and Δnf=s2nf−s2n−1fΔnf=s2nf−s2n−1f. Our results extend those known for Hardy or Bergman spaces and power weights ω(t)=tαω(t)=tα.

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Physical Sciences and Engineering Mathematics Analysis
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