{ "id": "math/0410047", "version": "v1", "published": "2004-10-04T08:24:27.000Z", "updated": "2004-10-04T08:24:27.000Z", "title": "Embedded spheres in S^2\\times S^1#...#S^2\\times S^1", "authors": [ "Siddhartha Gadgil" ], "comment": "8 pages", "categories": [ "math.GT", "math.GR" ], "abstract": "We give an algorithm to decide which elements of pi_2(S^2\\times S^1#...#S^2\\times S^1) can be represented by embedded spheres. Such spheres correspond to splittings of the free group on k generators. Equivalently our algorithm decides whether, for a handlebody N, an element in pi_2(N,\\partial N) can be represented by an embedded disc. We also give an algorithm to decide when classes in $\\pi_2(S^2\\times S^1#...#S^2\\times S^1)$ can be represented by disjoint embedded spheres. We introduce the splitting complex of a free group which is analogous to the complex of curves of a surface. We show that the splitting complex of the free group on k generators embeds in the complex of curves of a surface of genus $k$ as a quasi-convex subset.", "revisions": [ { "version": "v1", "updated": "2004-10-04T08:24:27.000Z" } ], "analyses": { "subjects": [ "57M05", "57M07", "20E06" ], "keywords": [ "free group", "splitting complex", "quasi-convex subset", "disjoint embedded spheres", "spheres correspond" ], "note": { "typesetting": "TeX", "pages": 8, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2004math.....10047G" } } }