{ "id": "1704.06624", "version": "v1", "published": "2017-04-21T16:39:52.000Z", "updated": "2017-04-21T16:39:52.000Z", "title": "Natural extensions of unimodal maps: prime ends of planar embeddings and semi-conjugacy to sphere homeomorphisms", "authors": [ "Philip Boyland", "André de Carvalho", "Toby Hall" ], "comment": "72 pages, 14 figures", "categories": [ "math.DS" ], "abstract": "Let $f\\colon I\\to I$ be a unimodal map with topological entropy $h(f)>\\frac12\\log2$, and let $\\widehat{f}\\colon\\widehat{I}\\to\\widehat{I}$ be its natural extension, where $\\widehat{I}=\\varprojlim(I,f)$. Subject to some regularity conditions, which are satisfied for tent maps and quadratic maps, we give a complete description of the prime ends of the Barge-Martin embedding of $\\widehat{I}$ into the disk, and identify the prime ends rotation number with the height of $f$. We also show that $\\widehat{f}$ is semi-conjugate to a sphere homeomorphism by a semi-conjugacy for which all fibers except one contain at most three points. In the case where $f$ is a post-critically finite tent map, we show that the corresponding sphere homeomorphism is a generalized pseudo-Anosov map.", "revisions": [ { "version": "v1", "updated": "2017-04-21T16:39:52.000Z" } ], "analyses": { "subjects": [ "37E05", "37E30", "37B45" ], "keywords": [ "sphere homeomorphism", "unimodal map", "natural extension", "planar embeddings", "semi-conjugacy" ], "note": { "typesetting": "TeX", "pages": 72, "language": "en", "license": "arXiv", "status": "editable" } } }