{ "id": "2212.10811", "version": "v1", "published": "2022-12-21T06:58:48.000Z", "updated": "2022-12-21T06:58:48.000Z", "title": "Mean Rational Approximation for Compact Subsets with Thin Boundaries", "authors": [ "John B. Conway", "Liming Yang" ], "comment": "arXiv admin note: text overlap with arXiv:1904.06446, arXiv:2212.05392", "categories": [ "math.FA" ], "abstract": "In 1991, J. Thomson obtained a celebrated decomposition theorem for $P^t(\\mu),$ the closed subspace of $L^t(\\mu)$ spanned by the analytic polynomials, when $1 \\le t < \\i.$ In 2008, J. Brennan \\cite{b08} generalized Thomson's theorem to $R^t(K, \\mu),$ the closed subspace of $L^t(\\mu)$ spanned by the rational functions with poles off a compact subset $K$ containing the support of $\\mu,$ when the diameters of the components of $\\mathbb C\\setminus K$ are bounded below. We obtain a necessary and sufficient condition for $R^t(K, \\mu)$ to ensure such a decomposition theorem holds", "revisions": [ { "version": "v1", "updated": "2022-12-21T06:58:48.000Z" } ], "analyses": { "keywords": [ "mean rational approximation", "compact subset", "thin boundaries", "decomposition theorem holds", "closed subspace" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }