{ "id": "1211.5441", "version": "v2", "published": "2012-11-23T09:02:11.000Z", "updated": "2012-11-27T12:44:22.000Z", "title": "Separating Models by Formulas and the Number of Countable Models", "authors": [ "Mohammad Assem" ], "categories": [ "math.LO" ], "abstract": "We indicate a way of distinguishing between structures, for which, two structures are said to be separable.Being separable implies being non-isomorphic. We show that for any first order theory $T$ in a countable language, if it has an uncountable set of countable models that are pairwise separable, then actually it has such a set of size $2^{\\aleph_0}$. Our result follows trivially assuming the Continuum Hypothesis ($CH$). We work here in $ZFC$ (only without $CH$).", "revisions": [ { "version": "v2", "updated": "2012-11-27T12:44:22.000Z" } ], "analyses": { "keywords": [ "countable models", "separating models", "first order theory", "structures", "continuum hypothesis" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2012arXiv1211.5441A" } } }