Retraction spaces and the homotopy metric |
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Authors: | Laurence Boxer |
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Affiliation: | Department of Mathematics, Muhlenberg College, Allentown, PA 18104, USA |
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Abstract: | Let X be a finite-dimensional compactum. Let (X) and (X) be the spaces of retractions and non-deformation retractions of X, respectively, with the compact-open (=sup-metric) topology. Let 2Xh be the space of non-empty compact ANR subsets of X with topology induced by the homotopy metric. Let RXh be the subspace of 2Xh consisting of the ANR's in X that are retracts of X.We show that (Sm) is simply-connected for m > 1. We show that if X is an ANR and A0?RXh, then limi→∞Ai=A0 in 2Xh if and only if for every retraction r0 of X onto A0 there are, for almost all i, retractions ri of X onto Ai such that limi→∞ri=ro in (X). We show that if X is an ANR, then the local connectedness of (X) implies that of RXh. We prove that (M) is locally connected if M is a closed surface. We give examples to show how some of our results weaken when X is not assumed to be an ANR. |
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Keywords: | 54B20 54C35 54C15 54F40 55D99 57A05 57A10 57A15 Retraction deformation retraction sup-metric finite dimensional compactum ANR homotopy metric Hausdorff metric homotopy domination FANR fundamental retraction movable |
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