{ "id": "math/0405473", "version": "v1", "published": "2004-05-25T17:50:38.000Z", "updated": "2004-05-25T17:50:38.000Z", "title": "The cardinal characteristic for relative gamma-sets", "authors": [ "Arnold W. Miller" ], "categories": [ "math.LO", "math.GN" ], "abstract": "For $X$ a separable metric space define $\\pp(X)$ to be the smallest cardinality of a subset $Z$ of $X$ which is not a relative $\\ga$-set in $X$, i.e., there exists an $\\om$-cover of $X$ with no $\\ga$-subcover of $Z$. We give a characterization of $\\pp(2^\\om)$ and $\\pp(\\om^\\om)$ in terms of definable free filters on $\\om$ which is related to the psuedointersection number $\\pp$. We show that for every uncountable standard analytic space $X$ that either $\\pp(X)=\\pp(2^\\om)$ or $\\pp(X)=\\pp(\\om^\\om)$. We show that both of following statements are each relatively consistent with ZFC: (a) $\\pp=\\pp(\\om^\\om) < \\pp(2^\\om)$ and (b) $\\pp < \\pp(\\om^\\om) =\\pp(2^\\om)$", "revisions": [ { "version": "v1", "updated": "2004-05-25T17:50:38.000Z" } ], "analyses": { "subjects": [ "03E35", "54D20", "03E50" ], "keywords": [ "cardinal characteristic", "relative gamma-sets", "separable metric space define", "uncountable standard analytic space", "smallest cardinality" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2004math......5473M" } } }