{ "id": "1006.0119", "version": "v3", "published": "2010-06-01T11:55:46.000Z", "updated": "2010-07-19T16:35:58.000Z", "title": "The topological fundamental group and free topological groups", "authors": [ "Jeremy Brazas" ], "comment": "33 pages", "journal": "Topology Appl. 158 (2011) pp. 779-802", "categories": [ "math.AT", "math.GN" ], "abstract": "The topological fundamental group $\\pi_{1}^{top}$ is a homotopy invariant finer than the usual fundamental group. It assigns to each space a quasitopological group and is discrete on spaces which admit universal covers. For an arbitrary space $X$, we compute the topological fundamental group of the suspension space $\\Sigma(X_+)$ and find that $\\pi_{1}^{top}(\\Sigma(X_+))$ either fails to be a topological group or is the free topological group on the path component space of $X$. Using this computation, we provide an abundance of counterexamples to the assertion that all topological fundamental groups are topological groups. A relation to free topological groups allows us to reduce the problem of characterizing Hausdorff spaces $X$ for which $\\pi_{1}^{top}(\\Sigma(X_+))$ is a Hausdorff topological group to some well known classification problems in topology.", "revisions": [ { "version": "v3", "updated": "2010-07-19T16:35:58.000Z" } ], "analyses": { "keywords": [ "topological fundamental group", "free topological group", "homotopy invariant finer", "admit universal covers", "path component space" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 33, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1006.0119B" } } }