{ "id": "1407.2148", "version": "v1", "published": "2014-07-08T16:06:41.000Z", "updated": "2014-07-08T16:06:41.000Z", "title": "Open book decompositions versus prime factorizations of closed, oriented 3-manifolds", "authors": [ "Paolo Ghiggini", "Paolo Lisca" ], "comment": "8 pages, 1 figure. Submitted to the proceedings of the conference \"Interactions between low dimensional topology and mapping class groups\", July 1-5, 2013, Max Planck Institute for Mathematics, Bonn", "categories": [ "math.GT" ], "abstract": "Let $M$ be a closed, oriented, connected 3--manifold and $(B,\\pi)$ an open book decomposition on $M$ with page $\\Sigma$ and monodromy $\\varphi$. It is easy to see that the first Betti number of $\\Sigma$ is bounded below by the number of $S^2\\times S^1$--factors in the prime factorization of $M$. Our main result is that equality is realized if and only if $\\varphi$ is trivial and $M$ is a connected sum of $S^2\\times S^1$'s. We also give some applications of our main result, such as a new proof of the result by Birman and Menasco that if the closure of a braid with $n$ strands is the unlink with $n$ components then the braid is trivial.", "revisions": [ { "version": "v1", "updated": "2014-07-08T16:06:41.000Z" } ], "analyses": { "subjects": [ "57N10", "57M25" ], "keywords": [ "open book decomposition", "prime factorization", "main result", "first betti number" ], "tags": [ "conference paper" ], "note": { "typesetting": "TeX", "pages": 8, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1407.2148G" } } }