{ "id": "1207.7342", "version": "v1", "published": "2012-07-31T18:52:21.000Z", "updated": "2012-07-31T18:52:21.000Z", "title": "Champagne subdomains with unavoidable bubbles", "authors": [ "Wolfhard Hansen", "Ivan Netuka" ], "comment": "12 pages. arXiv admin note: text overlap with arXiv:1206.1514", "categories": [ "math.AP" ], "abstract": "A champagne subdomain of a connected open set $U\\ne\\emptyset$ in $R^d$, $d\\ge 2$, is obtained omitting pairwise disjoint closed balls $\\bar{B}(x,r_x)$, $x\\in X$, the bubbles, where $X$ is an infinite, locally finite set in $U$. The union $A$ of these balls may be unavoidable, that is, Brownian motion, starting in $U\\setminus A$ and killed when leaving $U$, may hit $A$ almost surely or, equivalently, $A$ may have harmonic measure one for $U\\setminus A$. Recent publications by Gardiner/Ghergu ($d\\ge 3$) and by Pres ($d=2$) give rather sharp answers to the question how small such a set $A$ may be, when $U$ is the unit ball. In this paper, using a totally different approach, optimal results are obtained, results which hold as well for arbitrary connected open sets $U$.", "revisions": [ { "version": "v1", "updated": "2012-07-31T18:52:21.000Z" } ], "analyses": { "subjects": [ "31A15", "31B15", "60J65" ], "keywords": [ "champagne subdomain", "unavoidable bubbles", "arbitrary connected open sets", "locally finite set", "brownian motion" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2012arXiv1207.7342H" } } }