{ "id": "2312.13638", "version": "v1", "published": "2023-12-21T08:03:45.000Z", "updated": "2023-12-21T08:03:45.000Z", "title": "Colouring defect of a cubic graph and the conjectures of Fan-Raspaud and Fulkerson", "authors": [ "Ján Karabáš", "Edita Máčajová", "Roman Nedela", "Martin Škoviera" ], "categories": [ "math.CO" ], "abstract": "We introduce a new invariant of a cubic graph - its regular defect - which is defined as the smallest number of edges left uncovered by any collection of three perfect matchings that have no edge in common. This invariant is a modification of defect, an invariant introduced by Steffen (J. Graph Theory 78 (2015), 195--206), whose definition does not require the empty intersection condition. In this paper we discuss the relationship of this invariant to the well-known conjectures of Fulkerson (1971) and Fan and Raspaud (1994) and prove that defect and regular defect can be arbitrarily far apart.", "revisions": [ { "version": "v1", "updated": "2023-12-21T08:03:45.000Z" } ], "analyses": { "subjects": [ "05C15", "05C70" ], "keywords": [ "cubic graph", "colouring defect", "fan-raspaud", "regular defect", "empty intersection condition" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }