Fleissner, William G.2015-02-192015-02-191983-08-02Flesinner, William G. "Discrete Sets of Singular Cardinality." Proc. AMS. (1983) 88, 4. 743-745. http://www.dx.doi.org/10.1090/S0002-9939-1983-0702311-9.https://hdl.handle.net/1808/16728This is the published version, also available here: http://www.dx.doi.org/10.1090/S0002-9939-1983-0702311-9. First published in Proceedings of the AMS in 1983, published by the American Mathematical Society.Let « be a singular cardinal. In Fleissner's thesis, he showed that in normal spaces X, certain discrete sets Y of cardinality a (called here sparse) which are < ic-separated are, in fact, separated. In Watson's thesis, he proves the same for countably paracompact spaces X. Here we improve these results by making no assumption on the space X. As a corollary, we get that assuming V = L, S,-paralindelöf 7", spaces of character « co, are collectionwise Hausdorff.Discretesingular cardinalscollectionsiws HausdorffArticle10.1090/S0002-9939-1983-0702311-9openAccess