{ "id": "1512.00542", "version": "v1", "published": "2015-12-02T01:51:23.000Z", "updated": "2015-12-02T01:51:23.000Z", "title": "Quotient and blow-up of automorphisms of graphs of groups", "authors": [ "Kaidi Ye" ], "categories": [ "math.GR" ], "abstract": "In this paper we study the quotient and \"blow-up\" of graph-of-groups $\\cal{G}$ and of their automorphisms $H: \\cal{G} \\rightarrow \\cal{G}$. We show that the existence of such a \"blow-up\" of $\\bar{H}: \\bar{\\cal{G}} \\rightarrow \\bar{\\cal{G}}$ relative to a given family of \"local\" graph-of-groups isomorphisms $H_{i}: \\cal{G}_{i} \\rightarrow \\cal{G}_{i}$ depends crucially on the $H_{i}$-conjugacy class of the correction term $\\delta(\\bar{E}_{i})$ for any edge $\\bar{E}_{i}$ of $\\bar{\\cal{G}}$, where $H$-congjugacy is a new but natural concept introduced here. As an application we obtain a criterion as to whether a partial Dehn twist can be blown up relative to local Dehn twists to give an actual Dehn twist.", "revisions": [ { "version": "v1", "updated": "2015-12-02T01:51:23.000Z" } ], "analyses": { "keywords": [ "automorphisms", "actual dehn twist", "partial dehn twist", "local dehn twists", "conjugacy class" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }