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A short proof of Ellentuck's theorem - MaRDI portal

A short proof of Ellentuck's theorem (Q2701600)

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A short proof of Ellentuck's theorem
scientific article

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    19 February 2001
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    Ellentuck topology
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    completely Ramsey set
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    Baire property
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    A short proof of Ellentuck's theorem (English)
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    The author offers a short proof of Ellentuck's theorem that characterizes the completely Ramsey subsets of \([\omega]^\omega\) as those having the Baire property with respect to what is now known as the Ellentuck topology. The key step is a technical lemma that readily implies the following two facts: Ellentuck open sets are completely Ramsey and the family of Ellentuck nowhere dense sets is closed under countable unions. From this the main theorem follows at once.
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