Cozero-accessible points (Q1032899)
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scientific article; zbMATH DE number 5625459
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | Cozero-accessible points |
scientific article; zbMATH DE number 5625459 |
Statements
Cozero-accessible points (English)
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5 November 2009
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According to the author a point \(x\) in a space \(X\) is said to be cozero-accessible if for each dense open set \(U\subset X\) there is a cozero-set \(C\subset U\) such that \(x \in \overline{C}\). It is consistent with \(MA + \neg CH\) that there are cozero-accessible points in \(\beta \mathbb N \setminus \mathbb N\), while \(PFA\) implies that there are no such points in \(\beta \mathbb N \setminus \mathbb N\). Five interesting questions are posed.
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\(\beta\mathbb N\)
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cozero-accessible
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nowhere dense \(P\)-sets
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MA
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PFA
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0.73950124
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