{ "id": "1004.5308", "version": "v2", "published": "2010-04-29T14:41:17.000Z", "updated": "2011-01-25T06:36:46.000Z", "title": "Periodic elements in Garside groups", "authors": [ "Eon-Kyung Lee", "Sang-Jin Lee" ], "comment": "The contents of the 8-page paper \"Notes on periodic elements of Garside groups\" (arXiv:0808.0308) have been subsumed into this version. 27 pages", "journal": "Journal of Pure and Applied Algebra, vol. 215, no. 10, pp. 2295-2314, 2011", "doi": "10.1016/j.jpaa.2010.12.011", "categories": [ "math.GT", "math.GR" ], "abstract": "Let $G$ be a Garside group with Garside element $\\Delta$, and let $\\Delta^m$ be the minimal positive central power of $\\Delta$. An element $g\\in G$ is said to be 'periodic' if some power of it is a power of $\\Delta$. In this paper, we study periodic elements in Garside groups and their conjugacy classes. We show that the periodicity of an element does not depend on the choice of a particular Garside structure if and only if the center of $G$ is cyclic; if $g^k=\\Delta^{ka}$ for some nonzero integer $k$, then $g$ is conjugate to $\\Delta^a$; every finite subgroup of the quotient group $G/<\\Delta^m>$ is cyclic. By a classical theorem of Brouwer, Ker\\'ekj\\'art\\'o and Eilenberg, an $n$-braid is periodic if and only if it is conjugate to a power of one of two specific roots of $\\Delta^2$. We generalize this to Garside groups by showing that every periodic element is conjugate to a power of a root of $\\Delta^m$. We introduce the notions of slimness and precentrality for periodic elements, and show that the super summit set of a slim, precentral periodic element is closed under any partial cycling. For the conjugacy problem, we may assume the slimness without loss of generality. For the Artin groups of type $A_n$, $B_n$, $D_n$, $I_2(e)$ and the braid group of the complex reflection group of type $(e,e,n)$, endowed with the dual Garside structure, we may further assume the precentrality.", "revisions": [ { "version": "v2", "updated": "2011-01-25T06:36:46.000Z" } ], "analyses": { "subjects": [ "20F36", "20F10" ], "keywords": [ "garside group", "minimal positive central power", "complex reflection group", "dual garside structure", "precentral periodic element" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 27, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1004.5308L" } } }