{ "id": "2002.01297", "version": "v1", "published": "2020-02-04T14:24:55.000Z", "updated": "2020-02-04T14:24:55.000Z", "title": "Induced Ramsey number for a star versus a fixed graph", "authors": [ "Maria Axenovich", "Izolda Gorgol" ], "categories": [ "math.CO" ], "abstract": "For graphs G and H, let the induced Ramsey number IR(H,G) be the smallest number of vertices in a graph F such that any coloring of the edges of F in red and blue, there is either a red induced copy of H or a blue induced copy of G. In this note we consider the case when G=Sn is a star on n edges, for large n, and H is a fixed graph. We prove that (r-1)n < IR(H, Sn) < (r-1)(r-1)n + cn, for any c>0, sufficiently large n, and r denoting the chromatic number of H. The lower bound is asymptotically tight for any fixed bipartite H. The upper bound is attained up to a constant factor, for example by a clique H.", "revisions": [ { "version": "v1", "updated": "2020-02-04T14:24:55.000Z" } ], "analyses": { "keywords": [ "fixed graph", "induced ramsey number ir", "constant factor", "upper bound", "smallest number" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }