{ "id": "1911.00434", "version": "v1", "published": "2019-11-01T15:53:25.000Z", "updated": "2019-11-01T15:53:25.000Z", "title": "Consistency of $\\neg AC^{3}$ + $`χ(E_{G_{1}})=3$, $χ(E_{G_{2}})\\geqω\\impliesχ(E_{G_{1}\\times G_{2}})=3$' and relative consistency via strongly compactness", "authors": [ "Amitayu Banerjee", "Zalán Gyenis" ], "categories": [ "math.LO" ], "abstract": "We prove Andr\\'as Hajnal's \\textbf{Theorem 2} of \\cite{Haj1985} in different ways and observe a {\\em permutation model} where the {\\em axiom of choice for 3 element sets} fails but the statement in \\textbf{Theorem 2} of \\cite{Haj1985} still holds for $k=3$. We also observe that the {\\em Dilworth's decomposition theorem for infinite p.o.sets of finite width} holds and a weaker form of {\\L}o\\'{s}'s lemma (p. 253 of \\cite{HoRu1998}) fails in the permutation model of \\textbf{Theorem 7} of \\cite{HT2018} due to Lorenz Halbeisen and Eleftherios Tachtsis. Secondly, we weaken the large cardinal assumption of the results from \\cite{AC2013} due to Arthur Apter and Brent Cody, from a supercompact cardinal to a strongly compact cardinal. Further, applying the {\\em appropriate automorphism technique} from \\cite{AH1991} we remove the additional assumption that {\\em `every strongly compact cardinal is a limit of measurable cardinals'} from \\textbf{corollary 2.32} of section 4, chapter 2 of \\cite{Dim2011} by Ioanna Dimitriou.", "revisions": [ { "version": "v1", "updated": "2019-11-01T15:53:25.000Z" } ], "analyses": { "keywords": [ "strongly compactness", "relative consistency", "strongly compact cardinal", "permutation model", "dilworths decomposition theorem" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }