{ "id": "0907.4642", "version": "v4", "published": "2009-07-27T14:34:01.000Z", "updated": "2014-03-05T15:11:13.000Z", "title": "A combinatorial proof of the Degree Theorem in Auter space", "authors": [ "Robert McEwen", "Matthew C. B. Zaremsky" ], "comment": "Final version, in New York J. Math. (http://nyjm.albany.edu/j/2014/20-13.html). Minor changes from v3. 12 pages, 2 figures", "categories": [ "math.GR" ], "abstract": "We use discrete Morse theory to give a new proof of the Degree Theorem in Auter space A_n. There is a filtration of A_n into subspaces A_{n,k} using the degree of a graph, and the Degree Theorem says that each A_{n,k} is (k-1)-connected. This result is useful, for example to calculate stability bounds for the homology of Aut(F_n). The standard proof of the Degree Theorem is global in nature. Here we give a proof that only uses local considerations, and lends itself more readily to generalization.", "revisions": [ { "version": "v4", "updated": "2014-03-05T15:11:13.000Z" } ], "analyses": { "subjects": [ "20F65", "57M07", "20F28" ], "keywords": [ "auter space", "combinatorial proof", "degree theorem says", "discrete morse theory", "stability bounds" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2009arXiv0907.4642M" } } }