{ "id": "1312.5401", "version": "v2", "published": "2013-12-19T04:12:53.000Z", "updated": "2015-04-30T02:45:04.000Z", "title": "Fan-extensions in fragile matroids", "authors": [ "Carolyn Chun", "Deborah Chun", "Dillon Mayhew", "Stefan H. M. van Zwam" ], "comment": "Small revisions and corrections", "categories": [ "math.CO" ], "abstract": "If S is a set of matroids, then the matroid M is S-fragile if, for every element e in E(M), either M\\e or M/e has no minor isomorphic to a member of S. Excluded-minor characterizations often depend, implicitly or explicitly, on understanding classes of fragile matroids. In certain cases, when F is a minor-closed class of S-fragile matroids, and N is in F, the only members of F that contain N as a minor are obtained from N by increasing the length of fans. We prove that if this is the case, then we can certify it with a finite case-analysis. The analysis involves examining matroids that are at most two elements larger than N.", "revisions": [ { "version": "v1", "updated": "2013-12-19T04:12:53.000Z", "comment": "56 pages, 5 figures", "journal": null, "doi": null }, { "version": "v2", "updated": "2015-04-30T02:45:04.000Z" } ], "analyses": { "subjects": [ "05B35" ], "keywords": [ "fan-extensions", "minor isomorphic", "elements larger", "excluded-minor characterizations", "finite case-analysis" ], "note": { "typesetting": "TeX", "pages": 56, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1312.5401C" } } }