Rational and polynomial interpolation of analytic functions with restricted growth (Q5958887)

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scientific article; zbMATH DE number 1721769
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Rational and polynomial interpolation of analytic functions with restricted growth
scientific article; zbMATH DE number 1721769

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    Rational and polynomial interpolation of analytic functions with restricted growth (English)
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    16 September 2002
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    Consider a domain \(D\subset \overline \mathbb{C}=\mathbb{C}\cup \{\infty\}\) and an analytic function \(f\) on \(D\). Let for each \(n\geq 1\), \(A_n= \{a_{ni}\}^n_{i=0} \subset D\) and \(B_n=\{b_{n_i}\}^n_{i=1} \subset\mathbb{C}\) be two collections of points (some \(a_{n_i}\) or some \(b_{n_i}\) may coincide). Then there exists a unique rational function \(r_n\), of order \(n\) (the degree of numerator and the degree of denominator are at most \(n)\), with poles at \(B_n\), interpolating to \(f\) at \(A_n\), counting multiplicities. If \(A_n\) and \(B_n\) have some common points, we cancel them in the construction of \(r_n\). In this paper, the author examines the question: Given \(D\), is it possible to choose poles \(B_n\) and interpolating points \(A_n\) in such a way that for all analytic \(f\), \(r_n\) converges to \(f\). Uniformly on compact subsets of \(D\), as \(n\to \infty\)?
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    rational interpolation
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    polynomial interpolation
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    analytic functions
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    logarithmic potentials
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