{ "id": "1810.12489", "version": "v1", "published": "2018-10-30T02:09:09.000Z", "updated": "2018-10-30T02:09:09.000Z", "title": "Geodesics in the mapping class group", "authors": [ "Kasra Rafi", "Yvon Verberne" ], "comment": "16 pages, 3 figures", "categories": [ "math.GR", "math.GT" ], "abstract": "We construct explicit examples of geodesics in the mapping class group and show that the shadow of a geodesic in mapping class group to the curve graph does not have to be a quasi-geodesic. We also show that the quasi-axis of a pseudo-Anosov element of the mapping class group may not have the strong contractibility property. Specifically, we show that, after choosing a generating set carefully, one can find a pseudo-Anosov homeomorphism f, a sequence of points w_k and a sequence of radii r_k so that the ball B(w_k, r_k) is disjoint from a quasi-axis a of f, but for any projection map from mapping class group to a, the diameter of the image of B(w_k, r_k) grows like log(r_k).", "revisions": [ { "version": "v1", "updated": "2018-10-30T02:09:09.000Z" } ], "analyses": { "subjects": [ "37E30", "20F34", "57M07" ], "keywords": [ "mapping class group", "construct explicit examples", "strong contractibility property", "pseudo-anosov element", "curve graph" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable" } } }