On the weight-spectrum of a compact space (Q1261902)
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scientific article; zbMATH DE number 410024
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | On the weight-spectrum of a compact space |
scientific article; zbMATH DE number 410024 |
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On the weight-spectrum of a compact space (English)
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7 September 1993
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For a space \(X\) \(Sp (w,X)\) denotes the set of weights of all infinite closed subspaces of \(X\); this set is called the weight spectrum of \(X\). The author studies the weight spectrum of compact Hausdorff spaces. If \(k\) is an uncountable regular cardinal and \(X\) is a compact \(T_ 2\) space with \(w(X) \geq k\), then \(Sp (w,X) \cap [k,2^{<k}] \neq \emptyset\). Two (known) corollaries of this theorem are: (1) every \(\omega\)- monolithic compact space with a small diagonal is metrizable; (2) under CH every compact space with a small diagonal is metrizable. The following result is both consistent with and independent of ZFC: For an infinite cardinal \(k\) with \(\omega_ 1 < k < c\) there is a separable compact LOTS \(X\) such that \(Sp(w,X) = \{\omega, k\}\). It is consistent with the continuum hypothesis that for every countable closed set \(T\) of cardinals \(<c\) there exists a separable compact LOTS \(X\) such that \(Sp (w,X) = \{\omega\} \cup T\).
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\(MA(\sigma\)-centered)
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\(\omega\)-monolithic compact space
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weight spectrum
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small diagonal
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compact LOTS
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0.9014851
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0.89476967
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0.89410275
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0.8925882
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