Lifting the Collins-Roscoe property by condensations (Q2850634)
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scientific article; zbMATH DE number 6212840
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | Lifting the Collins-Roscoe property by condensations |
scientific article; zbMATH DE number 6212840 |
Statements
27 September 2013
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Collins-Roscoe property
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condensation
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Gul'ko compact space
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Lindelöf \(\Sigma\)-space
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metrizability
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monotonically \(\kappa\)-monolithic space
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\(\Sigma_s\)-product
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strongly monotonically monolithic space
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weakly \(\sigma\)-point-finite family
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0.74284697
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0.7417296
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0.72305006
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0.71124554
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0.7096755
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0.7070863
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Lifting the Collins-Roscoe property by condensations (English)
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If there exists a condensation (a continuous bijection) from a compact space \(X\) onto a space with a topological property \(\mathcal{P}\), then, since the map is a homeomorphism, \(X\) has \(\mathcal{P}\). In this paper, the author presents results of this type for the class of Lindelöf \(\Sigma\)-spaces which contains the class of compact spaces. Indeed, he shows that if a Lindelöf \(\Sigma\)-space \(X\) condenses onto a monotonically monolithic space (a space with the Collins-Roscoe property), then \(X\) is monotonically monolithic (has the Collins-Roscoe property). Furthermore, he gives the following results with respect to monotonic monolithicity and the Collins-Roscoe property: if \(X\) is a monotonically \(\omega\)-monolithic perfect normal compact space, then \(X\) is metrizable; if \(X\) is a strongly monotonically monolithic Lindelöf \(\Sigma\)-space, then \(X\) is second countable; if a Lindelöf \(\Sigma\)-space \(X\) condenses into a \(\Sigma_s\)-product of spaces of countable \(i\)-weight, then \(X\) has the Collins-Roscoe property. He also gives a negative answer to a question of \textit{G. Gruenhage} in [Topology Appl. 159, No. 6, 1559--1564 (2012; Zbl 1241.54013)], that is, he proves that there exists a compact space which is not Gul'ko compact but has the Collins-Roscoe property.
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