{ "id": "1610.00878", "version": "v1", "published": "2016-10-04T07:33:31.000Z", "updated": "2016-10-04T07:33:31.000Z", "title": "Reverse mathematics of the finite downwards closed subsets of $\\mathbb{N}^k$ ordered by inclusion", "authors": [ "Florian Pelupessy" ], "categories": [ "math.LO" ], "abstract": "We show that the well-partial orderedness of the finite downwards closed subsets of $\\mathbb{N}^k$ ,ordered by inclusion, is equivalent to the well-foundedness of the ordinal $\\omega^{\\omega^\\omega}$. This was conjectured to be so by Hatzikiriakou and Simpson.", "revisions": [ { "version": "v1", "updated": "2016-10-04T07:33:31.000Z" } ], "analyses": { "subjects": [ "03B30", "03F15", "06A06" ], "keywords": [ "finite downwards closed subsets", "reverse mathematics", "well-partial orderedness", "equivalent" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }