Embeddings into pseudocompact spaces of countable tightness. (Q1426485)
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scientific article; zbMATH DE number 2056824
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | Embeddings into pseudocompact spaces of countable tightness. |
scientific article; zbMATH DE number 2056824 |
Statements
Embeddings into pseudocompact spaces of countable tightness. (English)
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14 March 2004
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Under the existence of scales of cardinality \(\omega_1\) which is implied by CH, the following important result is proved. Let \({\mathfrak F}\) be a free filter on \(\omega\). We assume that \({\mathfrak F}\) has a base which is well ordered by \(\subset^*\) of type \(\omega_1\). Then there exists a pseudocompact \(0\)-dimensional \(T_1\)-space of countable tightness which has a closed subspace homeomorphic to \(\omega\cup\{{\mathfrak F}\}\). The symbol \(\subset^*\) means \(B- A\) is finite. Moreover, two existence theorems are stated under CH that are concerned with pseudocompact Tikhonov spaces of countable tightness. If \(p\in \beta\omega- \omega\) is a P-point (i.e., if every \(G_\delta\) which contains a point \(a\) is a neighborhood of \(a\), then \(a\) is a P-point), then there exists a pseudocompact Tikhonov space of countable tightness which contains a closed copy of \(\omega\cup\{p\}\subset \beta\omega\). \(\beta\omega\) is the Čech compactification of \(\omega\). Another one is: there exists a pseudocompact Tikhonov space of countable tightness which contains a non-discrete extremally disconnected subspace.
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Countable tightness
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Countable fan tightness
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Sequential spaces
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Pseudocompactness
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P-points
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Extremally disconnected spaces
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0.91428983
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0.90479106
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0.9031568
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0.8968886
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0.89567894
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0.8946091
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0.8935688
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0.8933629
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