{ "id": "math/9305204", "version": "v1", "published": "1993-05-15T00:00:00.000Z", "updated": "1993-05-15T00:00:00.000Z", "title": "The Ehrenfeucht-Fraisse-game of length omega_1", "authors": [ "Alan H. Mekler", "Saharon Shelah", "Jouko Väänänen" ], "journal": "Trans. Amer. Math. Soc. 339 (1993), 567--580", "categories": [ "math.LO" ], "abstract": "Let (A) and (B) be two first order structures of the same vocabulary. We shall consider the Ehrenfeucht-Fra{i}sse-game of length omega_1 of A and B which we denote by G_{omega_1}(A,B). This game is like the ordinary Ehrenfeucht-Fraisse-game of L_{omega omega} except that there are omega_1 moves. It is clear that G_{omega_1}(A,B) is determined if A and B are of cardinality <= aleph_1. We prove the following results: Theorem A: If V=L, then there are models A and B of cardinality aleph_2 such that the game G_{omega_1}(A,B) is non-determined. Theorem B: If it is consistent that there is a measurable cardinal, then it is consistent that G_{omega_1}(A,B) is determined for all A and B of cardinality <= aleph_2. Theorem C: For any kappa >= aleph_3 there are A and B of cardinality kappa such that the game G_{omega_1}(A,B) is non-determined.", "revisions": [ { "version": "v1", "updated": "1993-05-15T00:00:00.000Z" } ], "analyses": { "keywords": [ "first order structures", "ordinary ehrenfeucht-fraisse-game", "cardinality kappa", "vocabulary" ], "tags": [ "journal article" ], "publication": { "publisher": "AMS", "journal": "Trans. Amer. Math. Soc." }, "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "1993math......5204M" } } }