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\(\omega_1\)-strongly compact cardinals and normality - MaRDI portal

\(\omega_1\)-strongly compact cardinals and normality (Q2105035)

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scientific article; zbMATH DE number 7628718
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\(\omega_1\)-strongly compact cardinals and normality
scientific article; zbMATH DE number 7628718

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    \(\omega_1\)-strongly compact cardinals and normality (English)
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    8 December 2022
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    An uncountable cardinal \(\kappa\) is called \(\omega_1\)-strongly compact if every \(\kappa\)-complete filter can be extended to an \(\omega_1\)-complete ultrafilter. The main results in the present paper are: (i) for an \(\omega_1\)-strongly compact cardinal \(\kappa\), all normal Moore spaces are metrizable in a model obtained by adding \(\kappa\)-many random (or \(\kappa^+\)-many Cohen) reals; (ii) if \(\kappa_0\) is the least \(\omega_1\)-strongly compact cardinal, then for every first countable non-normal (resp. non-countably compact) topological space \(X\), there is a subspace \(Y\subseteq X\) of cardinality less than \(\kappa_0\) which is also non-normal (resp. non-countably compact).
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    \( \omega_1\)-strongly compact cardinals
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    normality
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    normal Moore space conjecture
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    compactness of normality
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    compactness of topological properties related to normality
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