{ "id": "1007.0189", "version": "v2", "published": "2010-07-01T14:57:29.000Z", "updated": "2010-11-06T14:53:26.000Z", "title": "Regionally proximal relation of order d is an equivalence one for minimal systems and a combinatorial consequence", "authors": [ "Song Shao", "Xiangdong Ye" ], "comment": "34 pages, 2 figures, the final version for submission", "categories": [ "math.DS" ], "abstract": "By proving the minimality of face transformations acting on the diagonal points and searching the points allowed in the minimal sets, it is shown that the regionally proximal relation of order $d$, $\\RP^{[d]}$, is an equivalence relation for minimal systems. Moreover, the lifting of $\\RP^{[d]}$ between two minimal systems is obtained, which implies that the factor induced by $\\RP^{[d]}$ is the maximal $d$-step nilfactor. The above results extend the same conclusions proved by Host, Kra and Maass for minimal distal systems. A combinatorial consequence is that if $S$ is a dynamically syndetic subset of $\\Z$, then for each $d\\ge 1$, $$\\{(n_1,\\...,n_d)\\in \\Z^d: n_1\\ep_1+... +n_d\\ep_d\\in S, \\ep_i\\in \\{0,1\\}, 1\\le i\\le d\\}$$ is syndetic. In some sense this is the topological correspondence of the result obtained by Host and Kra for positive upper Banach density subsets using ergodic methods.", "revisions": [ { "version": "v2", "updated": "2010-11-06T14:53:26.000Z" } ], "analyses": { "subjects": [ "37B05", "37A99" ], "keywords": [ "regionally proximal relation", "minimal systems", "combinatorial consequence", "equivalence", "positive upper banach density subsets" ], "note": { "typesetting": "TeX", "pages": 34, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1007.0189S" } } }