{ "id": "math/0703045", "version": "v5", "published": "2007-03-01T20:33:32.000Z", "updated": "2021-09-14T14:58:58.000Z", "title": "Definable groups for dependent and 2-dependent theories", "authors": [ "Saharon Shelah" ], "comment": "Version of 2017", "journal": "Sarajevo J. Math., 13(25)(1), (2017) 3-25", "doi": "10.5644/SJM.13.1.01", "categories": [ "math.LO" ], "abstract": "Let $T$ be a (first order complete) dependent theory, ${\\mathfrak{C}}$ a $\\bar\\kappa$-saturated model of $T$ and $G$ a definable subgroup which is abelian. Among subgroups of bounded index which are the union of $<\\bar\\kappa$ type definable subsets there is a minimal one, i.e. their intersection has bounded index. In fact, the bound is $\\leq 2^{|T|}$. We then deal with 2-dependent theories, a wider class of first order theories.", "revisions": [ { "version": "v4", "updated": "2010-09-08T02:56:21.000Z", "abstract": "Let T be a (first order complete) dependent theory, C a kappa-saturated model of T and G a definable subgroup which is abelian. Among subgroups of bounded index which are the union of < kappa type definable subsets there is a minimal one, i.e. their intersection has bounded index. In fact, the bound is <= 2^{|T|} . We then deal with 2-dependent theories, a wider class of first order theories.", "comment": null, "journal": null, "doi": null }, { "version": "v5", "updated": "2021-09-14T14:58:58.000Z" } ], "analyses": { "keywords": [ "definable groups", "first order complete", "kappa type definable subsets", "bounded index", "first order theories" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2007math......3045S" } } }