{ "id": "1210.7883", "version": "v1", "published": "2012-10-30T01:48:48.000Z", "updated": "2012-10-30T01:48:48.000Z", "title": "On Weak Elimination of Hyperimaginaries and its Consequences", "authors": [ "Donald Brower", "Cameron Donnay Hill" ], "comment": "16 pages", "categories": [ "math.LO" ], "abstract": "We analyze the notion of weak elimination of hyperimaginaries (WEHI) in simple theories. A key observation in the analysis is a characterization of WEHI in terms of forking dependence -- a condition we dub dependence-witnessed-by-imaginaries (DWIP). Generalizing results of [1] and [3], we show that in a simple theory with WEHI, forking and thorn-forking coincide. We also show that, conversely, the equivalence of independence and thorn-independence is (almost) sufficient for WEHI. Thus, the WEHI and the statement independence = thorn-independence are morally equivalent. As a further application of our technology, we demonstrate stable forking for 1-based theories of finite SU-rank that have WEHI.", "revisions": [ { "version": "v1", "updated": "2012-10-30T01:48:48.000Z" } ], "analyses": { "keywords": [ "weak elimination", "hyperimaginaries", "consequences", "simple theory", "dub dependence-witnessed-by-imaginaries" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2012arXiv1210.7883B" } } }