{ "id": "1310.8179", "version": "v2", "published": "2013-10-30T14:52:58.000Z", "updated": "2013-11-27T10:34:08.000Z", "title": "Almost isoperimetric subsets of the discrete cube", "authors": [ "David Ellis" ], "comment": "Typos corrected in Conjectures 12 and 13", "journal": "Combinatorics, Probability and Computing 20 (2011), 363-380", "categories": [ "math.CO" ], "abstract": "We show that a set $A \\subset \\{0,1\\}^{n}$ with edge-boundary of size at most $|A| (\\log_{2}(2^{n}/|A|) + \\epsilon)$ can be made into a subcube by at most $(2 \\epsilon/\\log_{2}(1/\\epsilon))|A|$ additions and deletions, provided $\\epsilon$ is less than an absolute constant. We deduce that if $A \\subset \\{0,1\\}^{n}$ has size $2^{t}$ for some $t \\in \\mathbb{N}$, and cannot be made into a subcube by fewer than $\\delta |A|$ additions and deletions, then its edge-boundary has size at least $|A| \\log_{2}(2^{n}/|A|) + |A| \\delta \\log_{2}(1/\\delta) = 2^{t}(n-t+\\delta \\log_{2}(1/\\delta))$, provided $\\delta$ is less than an absolute constant. This is sharp whenever $\\delta = 1/2^{j}$ for some $j \\in \\{1,2,\\ldots,t\\}$.", "revisions": [ { "version": "v2", "updated": "2013-11-27T10:34:08.000Z" } ], "analyses": { "subjects": [ "05D05" ], "keywords": [ "discrete cube", "isoperimetric subsets", "absolute constant", "edge-boundary" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1310.8179E" } } }