{ "id": "0812.1064", "version": "v1", "published": "2008-12-05T02:14:21.000Z", "updated": "2008-12-05T02:14:21.000Z", "title": "Graph Minors and Minimum Degree", "authors": [ "Gašper Fijavž", "David R. Wood" ], "journal": "Electronic J. Combinatorics R151, 2010", "categories": [ "math.CO" ], "abstract": "Let $\\mathcal{D}_k$ be the class of graphs for which every minor has minimum degree at most $k$. Then $\\mathcal{D}_k$ is closed under taking minors. By the Robertson-Seymour graph minor theorem, $\\mathcal{D}_k$ is characterised by a finite family of minor-minimal forbidden graphs, which we denote by $\\widehat{\\mathcal{D}}_k$. This paper discusses $\\widehat{\\mathcal{D}}_k$ and related topics. We obtain four main results: We prove that every $(k+1)$-regular graph with less than ${4/3}(k+2)$ vertices is in $\\widehat{\\mathcal{D}}_k$, and this bound is best possible. We characterise the graphs in $\\widehat{\\mathcal{D}}_{k+1}$ that can be obtained from a graph in $\\widehat{\\mathcal{D}}_k$ by adding one new vertex. For $k\\leq 3$ every graph in $\\widehat{\\mathcal{D}}_k$ is $(k+1)$-connected, but for large $k$, we exhibit graphs in $\\widehat{\\mathcal{D}}_k$ with connectivity 1. In fact, we construct graphs in $\\mathcal{D}_k$ with arbitrary block structure. We characterise the complete multipartite graphs in $\\widehat{\\mathcal{D}}_k$, and prove analogous characterisations with minimum degree replaced by connectivity, treewidth, or pathwidth.", "revisions": [ { "version": "v1", "updated": "2008-12-05T02:14:21.000Z" } ], "analyses": { "subjects": [ "05C83", "05C40" ], "keywords": [ "minimum degree", "robertson-seymour graph minor theorem", "minor-minimal forbidden graphs", "complete multipartite graphs", "characterise" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2008arXiv0812.1064F" } } }