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Proceedings of the American Mathematical Society

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On the failure of the first principle of separation for coanalytic sets


Author: Ashok Maitra
Journal: Proc. Amer. Math. Soc. 46 (1974), 299-301
MSC: Primary 54H05
MathSciNet review: 0356005
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Abstract: In this note we present a new example of a pair of disjoint coanalytic sets which are not Borel separable, i.e., coanalytic sets $ D$ and $ H$ such that $ D \cap H = \phi $ and such that there is no Borel set $ E$ for which $ D \subseteq E$ and $ E \cap H = \phi $.


References [Enhancements On Off] (What's this?)

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Additional Information

DOI: https://doi.org/10.1090/S0002-9939-1974-0356005-7
Keywords: Analytic sets, coanalytic sets, Borel separable, first principle of separation
Article copyright: © Copyright 1974 American Mathematical Society