Abstract:
Let the integer r⩾0 and the modulus of continuity ω(t) be fixed, and let CAr,ω be the class of all functions continuous on the closed unit disk ¯D, analytic on its interior D, and having an ω-continuous rth derivative on ¯D.
Consider for each f∈CAr,ω and each fixed ζ∈¯D the polynomial in z Pr,ζ(z;f)=r∑ν=0f(ν)(ζ)ν!
(the (r+1)st partial sum of the Taylor series of f in a neighborhood of ζ). Then for any two points ζ1,ζ2∈¯D |(Pr,ζ1(z)−Pr,ζ2(z))(ν)|z=ζ1⩽cf|ζ1−ζ2|r−νω(|ζ1−ζ2|),P⋅,⋅(⋅)=P⋅,⋅(⋅;f),0⩽ν⩽r.
Let E be a closed subset of ¯D. This article contains a solution of the problem of free interpolation in CAr,ω, formulated as follows: find necessary and sufficient conditions on E such that for each collection {Pζ}ζ∈E of rth-degree polynomials satisfying conditions of the type (1.1) for all ζ1,ζ2∈E there is a function f∈CAr,ω with Pζ(⋅)=Pr,ζ(⋅;f).
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This publication is cited in the following 6 articles:
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