{ "id": "1604.04415", "version": "v1", "published": "2016-04-15T09:48:18.000Z", "updated": "2016-04-15T09:48:18.000Z", "title": "The Grothendieck-Teichmüller group of $PSL(2, q)$", "authors": [ "Pierre Guillot" ], "comment": "7 pages", "categories": [ "math.GR", "math.NT" ], "abstract": "We show that the Grothendieck-Teichm\\\"uller group of $PSL(2, q)$, or more precisely the group $GT_1(PSL(2, q))$ as previously defined by the author, is the product of an elementary abelian 2-group and several copies of the dihedral group of order 8. Moreover, when $q$ is even, we show that it is trivial. We explain how it follows that the moduli field of any \"dessin d'enfant\" whose monodromy group is $PSL(2, q)$ has derived length less than 4. This paper can serve as an introduction to the general results on the Grothendieck-Teichm\\\"uller group of finite groups obtained by the author.", "revisions": [ { "version": "v1", "updated": "2016-04-15T09:48:18.000Z" } ], "analyses": { "keywords": [ "grothendieck-teichmüller group", "general results", "monodromy group", "elementary abelian", "dessin denfant" ], "note": { "typesetting": "TeX", "pages": 7, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2016arXiv160404415G" } } }