Nonnormality points of βX∖X
William Fleissner ; Lynne Yengulalp
Fundamenta Mathematicae, Tome 215 (2011), p. 269-283 / Harvested from The Polish Digital Mathematics Library
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Let X be a crowded metric space of weight κ that is either κω-like or locally compact. Let y ∈ βX∖X and assume GCH. Then a space of nonuniform ultrafilters embeds as a closed subspace of (βX∖X)∖y with y as the unique limit point. If, in addition, y is a regular z-ultrafilter, then the space of nonuniform ultrafilters is not normal, and hence (βX∖X)∖y is not normal.

Publié le : 2011-01-01
EUDML-ID : urn:eudml:doc:283333 
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William Fleissner; Lynne Yengulalp. Nonnormality points of βX∖X. Fundamenta Mathematicae, Tome 215 (2011) pp. 269-283. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm214-3-4/