{ "id": "math/0409087", "version": "v1", "published": "2004-09-06T17:43:13.000Z", "updated": "2004-09-06T17:43:13.000Z", "title": "Commutators and squares in free groups", "authors": [ "Sucharit Sarkar" ], "comment": "Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol4/agt-4-27.abs.html", "journal": "Algebr. Geom. Topol. 4 (2004) 595-602", "categories": [ "math.GR" ], "abstract": "Let F_2 be the free group generated by x and y. In this article, we prove that the commutator of x^m and y^n is a product of two squares if and only if mn is even. We also show using topological methods that there are infinitely many obstructions for an element in F_2 to be a product of two squares.", "revisions": [ { "version": "v1", "updated": "2004-09-06T17:43:13.000Z" } ], "analyses": { "subjects": [ "20F12", "57M07" ], "keywords": [ "commutator", "free group", "topological methods" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }