Analytic bounded point evaluations for spaces of rational functions (Q1316364)

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scientific article; zbMATH DE number 515223
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Analytic bounded point evaluations for spaces of rational functions
scientific article; zbMATH DE number 515223

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    Analytic bounded point evaluations for spaces of rational functions (English)
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    12 June 1995
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    For a compact subset of the complex plane \(K\) and a regular Borel measure \(\mu\) supported on \(K\), \(R^ p(K,\mu)\) denotes the closure in \(L^ p(\mu)\) of the rational functions with poles off \(K\). In this paper the existence of analytic bounded point evaluations on \(R^ p(K,\mu)\) is examined and the work of Thomson on the existence of analytic bounded point evaluations for the closure in \(L^ p(\mu)\) of the analytic polynomials is extended. Provided \(R^ p(K,\mu)\) is ``pure'', it is shown that the closure of the set of analytic bounded point evaluations for \(R^ p(K,\mu)\) equals the closure of the interior of the spectrum of the operator multiplication by \(z\) on \(R^ p(K,\mu)\). In fact this is derived as a consequence of Thomson's result for polynomials. The bulk of the paper is devoted to certain interpolation problems for \(R^ p(K,\mu)\), thus producing some information on the structure of \(R^ p(K,\mu)\).
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    existence of analytic bounded point evaluations
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    interpolation problems
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