{ "id": "1306.2662", "version": "v3", "published": "2013-06-11T21:33:57.000Z", "updated": "2014-04-03T13:36:29.000Z", "title": "Densely Defined Multiplication on the Sobolev Space", "authors": [ "Joel A. Rosenfeld" ], "comment": "10 pages", "categories": [ "math.FA" ], "abstract": "Following Sarason's classification of the densely defined multiplication operators over the Hardy space, we classify the densely defined multipliers over the Sobolev space, $W^{1,2}[0,1]$. In this paper we find that the collection of such multipliers for the Sobolev space is exactly the Sobolev space itself. This sharpens a result of Shields concerning bounded multipliers. The densely defined multiplication operators over the subspace $W_0 = \\{f \\in W^{1,2}[0,1] : f(0)=f(1)=0 \\}$ are also classified. In this case the densely defined multiplication operators can be written as a ratio of functions in $W_0$ where the denominator is non-vanishing. This is proved using a contructive argument.", "revisions": [ { "version": "v3", "updated": "2014-04-03T13:36:29.000Z" } ], "analyses": { "keywords": [ "sobolev space", "densely defined multiplication operators", "shields concerning bounded multipliers", "hardy space", "sarasons classification" ], "note": { "typesetting": "TeX", "pages": 10, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1306.2662R" } } }