{ "id": "1404.0151", "version": "v1", "published": "2014-04-01T07:55:53.000Z", "updated": "2014-04-01T07:55:53.000Z", "title": "Topological infinite gammoids, and a new Menger-type theorem for infinite graphs", "authors": [ "Johannes Carmesin" ], "categories": [ "math.CO" ], "abstract": "Answering a question of Diestel, we develop a topological notion of gammoids in infinite graphs which, unlike traditional infinite gammoids, always define a matroid. As our main tool, we prove for any infinite graph $G$ with vertex sets $A$ and $B$ that if every finite subset of $A$ is linked to $B$ by disjoint paths, then the whole of $A$ can be linked to the closure of $B$ by disjoint paths or rays in a natural topology on $G$ and its ends. This latter theorem re-proves and strengthens the infinite Menger theorem of Aharoni and Berger for `well-separated' sets $A$ and $B$. It also implies the topological Menger theorem of Diestel for locally finite graphs.", "revisions": [ { "version": "v1", "updated": "2014-04-01T07:55:53.000Z" } ], "analyses": { "subjects": [ "05C63" ], "keywords": [ "infinite graph", "topological infinite gammoids", "menger-type theorem", "disjoint paths", "infinite menger theorem" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1404.0151C" } } }