{ "id": "1606.00762", "version": "v1", "published": "2016-06-02T16:55:19.000Z", "updated": "2016-06-02T16:55:19.000Z", "title": "Multicolour Ramsey numbers of paths and even cycles", "authors": [ "Ewan Davies", "Matthew Jenssen", "Barnaby Roberts" ], "comment": "12 pages", "categories": [ "math.CO" ], "abstract": "We prove new upper bounds on the multicolour Ramsey numbers of paths and even cycles. It is well known that $(k-1)n+o(n)\\leq R_k(P_n)\\leq R_k(C_n)\\leq kn+o(n)$. The upper bound was recently improved by S\\'ark\\\"ozy who showed that $R_k(C_n)\\leq\\left(k-\\frac{k}{16k^3+1}\\right)n+o(n)$. Here we show $R_k(C_n) \\leq (k-\\frac14)n +o(n)$, obtaining the first improvement to the coefficient of the linear term by an absolute constant.", "revisions": [ { "version": "v1", "updated": "2016-06-02T16:55:19.000Z" } ], "analyses": { "subjects": [ "05C55", "05C38" ], "keywords": [ "multicolour ramsey numbers", "upper bound", "absolute constant", "first improvement", "linear term" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable" } } }