{ "id": "1401.2680", "version": "v3", "published": "2014-01-12T22:48:17.000Z", "updated": "2015-01-01T19:43:45.000Z", "title": "Spectra of Composition Operators with Symbols in S(2)", "authors": [ "Paul S. Bourdon" ], "comment": "19 pages, 1 figure, to appear in the Journal of Operator Theory", "categories": [ "math.FA" ], "abstract": "Let H^2(D) denote the classical Hardy space of the open unit disk D in the complex plane. We obtain descriptions of both the spectrum and essential spectrum of composition operators on H^2(D) whose symbols belong to the class S(2) introduced by Kriete and Moorhouse [Trans. Amer. Math. Soc., 359, 2007]. Our work reveals new possibilities for the shapes of composition-operator spectra, settling a conjecture of Cowen's [J. Operator Th. 9, 1983]. Our results depend on a number of lemmas, perhaps of independent interest, that provide spectral characterizations of sums of elements of a unital algebra over a field when certain pairwise products of the summands are zero.", "revisions": [ { "version": "v2", "updated": "2014-02-20T01:33:08.000Z", "comment": "19 pages, 1 figure, improved, submitted for publication", "journal": null, "doi": null }, { "version": "v3", "updated": "2015-01-01T19:43:45.000Z" } ], "analyses": { "subjects": [ "47B33", "47A10" ], "keywords": [ "composition operators", "open unit disk", "complex plane", "classical hardy space", "symbols belong" ], "note": { "typesetting": "TeX", "pages": 19, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1401.2680B" } } }