{ "id": "1804.04787", "version": "v1", "published": "2018-04-13T04:20:37.000Z", "updated": "2018-04-13T04:20:37.000Z", "title": "Unavoidable Subtournaments in Tournaments with Large Chromatic Number", "authors": [ "Ilhee Kim", "Ringi Kim" ], "categories": [ "math.CO" ], "abstract": "For a set H of tournaments, we say H is heroic if every tournament, not containing any member of H as a subtournament, has bounded chromatic number. Berger et al. explicitly characterized all heroic sets containing one tournament. Motivated by this result, we study heroic sets containing two tournaments. We give a necessary condition for a set containing two tournaments to be heroic. We also construct infinitely many minimal heroic sets of size two.", "revisions": [ { "version": "v1", "updated": "2018-04-13T04:20:37.000Z" } ], "analyses": { "keywords": [ "large chromatic number", "unavoidable subtournaments", "minimal heroic sets", "bounded chromatic number", "study heroic sets containing" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }