{ "id": "1405.2558", "version": "v1", "published": "2014-05-11T18:00:48.000Z", "updated": "2014-05-11T18:00:48.000Z", "title": "On a Hierarchy of Reflection Principles in Peano Arithmetic", "authors": [ "Elena Nogina" ], "comment": "13 pages", "categories": [ "math.LO" ], "abstract": "We study reflection principles of Peano Arithmetic PA which are based on both proof and provability. Any such reflection principle in PA is equivalent to either $\\Box P\\!\\rightarrow\\! P$ ($\\Box P$ stands for `$P$ is provable') or $\\Box^k u\\!\\!:\\!\\!P\\!\\rightarrow\\! P$ for some $k\\geq 0$ ($t:P$ states `$t$ is a proof of $P$'). Reflection principles constitute a non-collapsing hierarchy with respect to their deductive strength $$u\\!\\!:\\!\\!P\\!\\rightarrow\\! P\\ \\ \\prec\\ \\ \\Box u\\!\\!:\\!\\!P\\!\\rightarrow\\! P\\ \\ \\prec\\ \\ \\Box^2 u\\!\\!:\\!\\!P\\!\\rightarrow\\! P \\ \\ \\prec\\ \\ldots\\ \\prec\\ \\ \\Box P\\!\\rightarrow\\! P.$$", "revisions": [ { "version": "v1", "updated": "2014-05-11T18:00:48.000Z" } ], "analyses": { "subjects": [ "03F03", "03F25", "03F30", "03F45" ], "keywords": [ "study reflection principles", "peano arithmetic pa", "reflection principles constitute", "equivalent", "non-collapsing hierarchy" ], "note": { "typesetting": "TeX", "pages": 13, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1405.2558N" } } }