{ "id": "1803.09771", "version": "v2", "published": "2018-03-26T18:07:53.000Z", "updated": "2018-07-17T20:38:50.000Z", "title": "Pigeons do not jump high", "authors": [ "Benoit Monin", "Ludovic Patey" ], "comment": "20 pages", "categories": [ "math.LO" ], "abstract": "The infinite pigeonhole principle for 2-partitions asserts the existence, for every set $A$, of an infinite subset of $A$ or of its complement. In this paper, we develop a new notion of forcing enabling a fine analysis of the computability-theoretic features of the pigeonhole principle. We deduce various consequences, such as the existence, for every set $A$, of an infinite subset of it or its complement of non-high degree. We also prove that every $\\Delta^0_3$ set has an infinite low${}_3$ solution and give a simpler proof of Liu's theorem that every set has an infinite subset in it or its complement of non-PA degree.", "revisions": [ { "version": "v2", "updated": "2018-07-17T20:38:50.000Z" } ], "analyses": { "keywords": [ "jump high", "infinite subset", "infinite pigeonhole principle", "complement", "non-pa degree" ], "note": { "typesetting": "TeX", "pages": 20, "language": "en", "license": "arXiv", "status": "editable" } } }