{ "id": "1201.1610", "version": "v2", "published": "2012-01-08T06:00:26.000Z", "updated": "2012-09-13T08:52:20.000Z", "title": "On finite factors of centralizers of parabolic subgroups in Coxeter groups", "authors": [ "Koji Nuida" ], "comment": "44 pages, 4 figures, 19 tables, separated from Section 7 of arXiv:math/0501061v4 [math.GR] with improvements; (v2) 43 pages, 5 figures, 16 tables, the size of counterexample is reduced, some parts are slightly revised", "journal": "Tsukuba Journal of Mathematics, vol.36, no.2 (2012).235-294", "categories": [ "math.GR" ], "abstract": "It has been known that the centralizer $Z_W(W_I)$ of a parabolic subgroup $W_I$ of a Coxeter group $W$ is a split extension of a naturally defined reflection subgroup by a subgroup defined by a 2-cell complex $\\mathcal{Y}$. In this paper, we study the structure of $Z_W(W_I)$ further and show that, if $I$ has no irreducible components of type $A_n$ with $2 \\leq n < \\infty$, then every element of finite irreducible components of the inner factor is fixed by a natural action of the fundamental group of $\\mathcal{Y}$. This property has an application to the isomorphism problem in Coxeter groups.", "revisions": [ { "version": "v2", "updated": "2012-09-13T08:52:20.000Z" } ], "analyses": { "subjects": [ "20F55", "20E34" ], "keywords": [ "coxeter group", "parabolic subgroup", "finite factors", "centralizer", "split extension" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 44, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2012arXiv1201.1610N" } } }