{ "id": "1810.08847", "version": "v1", "published": "2018-10-20T19:51:14.000Z", "updated": "2018-10-20T19:51:14.000Z", "title": "The Mapping Class Group of a Minimal Subshift", "authors": [ "Scott Schmieding", "Kitty Yang" ], "categories": [ "math.DS" ], "abstract": "For a homeomorphism $T \\colon X \\to X$ of a Cantor set $X$, the mapping class group $\\mathcal{M}(T)$ is the group of isotopy classes of orientation-preserving self-homeomorphisms of the suspension $\\Sigma_{T}X$. The group $\\mathcal{M}(T)$ can be interpreted as the symmetry group of the system $(X,T)$ with respect to the flow equivalence relation. We study $\\mathcal{M}(T)$, focusing on the case when $(X,T)$ is a minimal subshift. We show that when $(X,T)$ is a subshift associated to a substitution, the group $\\mathcal{M}(T)$ is an extension of $\\mathbb{Z}$ by a finite group; for a large class of substitutions including Pisot type, this finite group is a quotient of the automorphism group of $(X,T)$. When $(X,T)$ is a minimal subshift of linear complexity satisfying a no-infinitesimals condition, we show that $\\mathcal{M}(T)$ is virtually abelian. We also show that when $(X,T)$ is minimal, $\\mathcal{M}(T)$ embeds into the Picard group of the crossed product algebra $C(X) \\rtimes_{T} \\mathbb{Z}$.", "revisions": [ { "version": "v1", "updated": "2018-10-20T19:51:14.000Z" } ], "analyses": { "keywords": [ "mapping class group", "minimal subshift", "finite group", "flow equivalence relation", "cantor set" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }