{ "id": "1308.0888", "version": "v2", "published": "2013-08-05T05:06:30.000Z", "updated": "2013-11-01T08:24:21.000Z", "title": "Subgroups of mapping class groups related to Heegaard splittings and bridge decompositions", "authors": [ "Ken'ichi Ohshika", "Makoto Sakuma" ], "comment": "19 pages: the second version. The assumption of Theorem 3 has been changed from the bounded geometry to the bounded combinatorics", "categories": [ "math.GT" ], "abstract": "Let $M=H_1\\cup_S H_2$ be a Heegaard splitting of a closed orientable 3-manifold $M$ (or a bridge decomposition of a link exterior). Consider the subgroup $\\mathrm{MCG}^0(H_j)$ of the mapping class group of $H_j$ consisting of mapping classes represented by auto-homeomorphisms of $H_j$ homotopic to the identity, and let $G_j$ be the subgroup of the automorphism group of the curve complex $\\mathcal{CC}(S)$ obtained as the image of $\\mathrm{MCG}^0(H_j)$. Then the group $G=$ generated by $G_1$ and $G_2$ preserve the homotopy class in $M$ of simple loops on $S$. In this paper, we study the structure of the group $G$ and the problem to what extent the converse to this observation holds.", "revisions": [ { "version": "v2", "updated": "2013-11-01T08:24:21.000Z" } ], "analyses": { "subjects": [ "57M50", "57M07", "30F40", "20F34" ], "keywords": [ "mapping class groups", "bridge decomposition", "heegaard splitting", "link exterior", "automorphism group" ], "note": { "typesetting": "TeX", "pages": 19, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1308.0888O" } } }