{ "id": "1906.04273", "version": "v1", "published": "2019-06-10T21:03:37.000Z", "updated": "2019-06-10T21:03:37.000Z", "title": "Independence in Arithmetic: The Method of $(\\mathcal L, n)$-Models", "authors": [ "Corey Bacal Switzer" ], "comment": "17 Pages", "categories": [ "math.LO", "math.CO" ], "abstract": "I develop in depth the machinery of $(\\mathcal L, n)$-models originally introduced by Shelah \\cite{ShelahPA} and, independently in a slightly different form by Kripke (cf \\cite{put2000}, \\cite{quin80}). This machinery allows fairly routine constructions of true but unprovable sentences in $\\mathsf{PA}$. I give three applications: 1. Shelah's alternative proof of the Paris-Harrington theorem, 2. The independence over $\\mathsf{PA}$ of a $\\Pi^0_1$ Ramsey theoretic statement about colorings of finite sequences of structures and 3. The independence over $\\mathsf{PA}$ of both a $\\Pi_2^0$-statement and a $\\Pi^0_1$-statement about choice functions for sequences of numbers and finite structures respectively. The latter is reminiscent of Shelah's example.", "revisions": [ { "version": "v1", "updated": "2019-06-10T21:03:37.000Z" } ], "analyses": { "subjects": [ "03C62", "03C98", "05D10" ], "keywords": [ "independence", "arithmetic", "ramsey theoretic statement", "shelahs alternative proof", "paris-harrington theorem" ], "note": { "typesetting": "TeX", "pages": 17, "language": "en", "license": "arXiv", "status": "editable" } } }