{ "id": "1408.0315", "version": "v2", "published": "2014-08-01T22:23:53.000Z", "updated": "2014-09-09T14:41:27.000Z", "title": "On better-quasi-ordering classes of partial orders", "authors": [ "Gregory McKay" ], "comment": "v1: 45 pages, 8 figures; v2: 44 pages, 11 figures, minor corrections, fixed typos, new figures and some notational changes to improve clarity", "categories": [ "math.LO" ], "abstract": "We provide a method of constructing better-quasi-orders by generalising a technique for constructing operator algebras that was developed by Pouzet. We then use this method to prove that certain transfinite classes of partial orders are better-quasi-ordered under embeddability. In particular, a class of countable partial orders is better-quasi-ordered whenever the class of indecomposable subsets of its members satisfies a natural strengthening of better-quasi-order. Our main result generalises theorems of Laver, Corominas and Thomass\\'e reguarding \\sigma-scattered linear orders and trees, countable forests and N-free partial orders respectively.", "revisions": [ { "version": "v1", "updated": "2014-08-01T22:23:53.000Z", "abstract": "We provide a method for constructing better-quasi-orders by generalising a technique developed by Pouzet. We then use this method to prove that certain large classes of partial orders are better-quasi-ordered under embeddability. This result generalises theorems of Laver, Corominas and Thomass\\'e.", "comment": "45 pages, 8 figures", "journal": null, "doi": null }, { "version": "v2", "updated": "2014-09-09T14:41:27.000Z" } ], "analyses": { "subjects": [ "06A07", "03E05", "06A06", "05C05" ], "keywords": [ "partial orders", "better-quasi-ordering classes", "result generalises theorems", "large classes", "constructing better-quasi-orders" ], "note": { "typesetting": "TeX", "pages": 45, "language": "en", "license": "arXiv", "status": "editable" } } }