On a problem by A. Hajnal and I. Juhász (Q1029940)
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scientific article; zbMATH DE number 5578070
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | On a problem by A. Hajnal and I. Juhász |
scientific article; zbMATH DE number 5578070 |
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On a problem by A. Hajnal and I. Juhász (English)
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14 July 2009
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\textit{A. Hajnal} and \textit{I. Juhász} asked in [Problems (p. 637), Topics in topology. Colloquia Mathematica Societatis Janos Bolyai. 8. Amsterdam-London: North-Holland Publishing Company. 643 p. (1974; Zbl 0278.00018)] whether \(\lambda^\omega=\lambda\) whenever \(\lambda\) is the cardinality of a Hausdorff topology on an infinite set. The authors describe an example with the claim that the cardinality of its topology is \(\aleph_\omega (<\aleph_\omega^{\;\omega})\). Unfortunately the topology has cellularity \(\aleph_\omega\) and hence cardinality \(2^{\aleph_\omega}\).
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number of open sets
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Hausdorff space
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