{ "id": "1808.09584", "version": "v1", "published": "2018-08-28T23:56:07.000Z", "updated": "2018-08-28T23:56:07.000Z", "title": "The hyperspace of non blockers of $F_1(X)$", "authors": [ "Javier Camargo", "David Maya", "Luis Ortiz" ], "categories": [ "math.GN" ], "abstract": "A continuum is a compact connected metric space. A non-empty closed subset $B$ of a continuum $X$ does not block $x\\in X\\setminus B$ provided that the union of all subcontinua of $X$ containing $x$ and contained in $X\\setminus B$ is dense in $X$. We denote the collection of all non-empty closed subset $B$ of $X$ such that $B$ does not block each element of $X\\setminus B$ by $NB(F_1(X))$. In this paper we show some properties of the hyperspace $NB(F_1(X))$. Particularly, we prove that the simple closed curve is the unique continuum $X$ such that $NB(F_1(X))=F_1(X)$, given a positive answer to a question posed by Escobedo, Estrada-Obreg\\'on and Villanueva in 2012.", "revisions": [ { "version": "v1", "updated": "2018-08-28T23:56:07.000Z" } ], "analyses": { "subjects": [ "54B20", "54F15" ], "keywords": [ "non blockers", "hyperspace", "non-empty closed subset", "compact connected metric space", "unique continuum" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }