{ "id": "math/0009087", "version": "v2", "published": "2000-09-08T13:37:11.000Z", "updated": "2011-04-14T23:40:19.000Z", "title": "On triangleleft^*-maximality", "authors": [ "Mirna Džamonja", "Saharon Shelah" ], "categories": [ "math.LO" ], "abstract": "This paper investigates a connection between the ordering triangleleft^ast among theories in model theory and the (N)SOP_n hierarchy of Shelah. It introduces two properties which are natural extensions of this hierarchy, called SOP_2 and SOP_1, and gives a strong connection between SOP_1 and the maximality in Keisler ordering. Together with the known results about the connection between the (N)SOP_n hierarchy and the existence of universal models in the absence of GCH, the paper provides a step toward the classification of unstable theories without the strict order property.", "revisions": [ { "version": "v2", "updated": "2011-04-14T23:40:19.000Z" } ], "analyses": { "keywords": [ "strict order property", "model theory", "natural extensions", "strong connection", "universal models" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2000math......9087D" } } }