{ "id": "math/0304086", "version": "v2", "published": "2003-04-07T05:06:19.000Z", "updated": "2003-11-25T02:44:51.000Z", "title": "Connectivity of finite subset spaces of cell complexes", "authors": [ "Christopher Tuffley" ], "comment": "4 pages. v2: retitled; main result strengthened for simply-connected complexes using math.GT/0311371, and problem of strengthening it for m-connected complexes reduced to strengthening it for wedges of (m+1)-spheres", "journal": "Pacific J. Math. 217(1):175-179 (2004)", "categories": [ "math.GT" ], "abstract": "The kth finite subset space of a topological space X is the space exp_k X of non-empty subsets of X of size at most k, topologised as a quotient of X^k. Using results from our earlier paper (math.GT/0210315) on the finite subset spaces of connected graphs we show that the kth finite subset space of a connected cell complex is (k-2)-connected, and (k-1)-connected if in addition the underlying space is simply connected. We expect exp_k X to be (k+m-2)-connected if X is an m-connected cell complex, and reduce proving this to the problem of proving it for finite wedges of (m+1)-spheres. Our results complement a theorem due to Handel that for path-connected Hausdorff X the map on pi_i induced by the inclusion exp_k X --> exp_{2k+1} X is zero for all k and i.", "revisions": [ { "version": "v2", "updated": "2003-11-25T02:44:51.000Z" } ], "analyses": { "subjects": [ "55R80", "54B20", "55Q52" ], "keywords": [ "kth finite subset space", "cell complexes", "connectivity", "earlier paper", "non-empty subsets" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 4, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2003math......4086T" } } }