Vol. 217, No. 1, 2004

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Connectivity of finite subset spaces of cell complexes

Christopher Tuffley

Vol. 217 (2004), No. 1, 175–179
Abstract

The k-th finite subset space of a topological space X is the space expk X of nonempty subsets of X of size at most k, topologised as a quotient of Xk. Using results from our earlier paper on the finite subset spaces of connected graphs we show that the k-th 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 expk X to be (k + m2)-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 πi induced by the inclusion expk Xexp2k+1 X is zero for all k1 and i 0.

Milestones
Published: 1 November 2004
Authors
Christopher Tuffley
Department of Mathematics
University of California at Davis
Davis CA 95616-8633