Characterization of compact spaces with noncoinciding dimensions which are subsets of products of simple spaces (Q952603)

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scientific article; zbMATH DE number 5365215
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Characterization of compact spaces with noncoinciding dimensions which are subsets of products of simple spaces
scientific article; zbMATH DE number 5365215

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    Characterization of compact spaces with noncoinciding dimensions which are subsets of products of simple spaces (English)
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    12 November 2008
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    First examples of compact spaces with noncoinciding classical dimensions ind and \(\dim\) were realized as closed subsets of the product of the long closed interval \([0,\omega_c]\), where \(\omega_c\) is the first ordinal of cardinality of the continuum, and the closed bounded interval \([0,1]\). In the present paper the author studies dimensional properties of closed subsets of products \(\Pi=[0,\omega_c] \times K\), where \(K\) is a metrizable compactum. The first result is the following: for any closed subset \(X\) of \(\Pi\) we have \(\operatorname{Ind}X \leq \dim X +1.\) This implies the splitting of all closed subsets \(X\) of \(\Pi\) into two classes: either \(\operatorname{Ind}X= \operatorname{ind}X= \dim X +1\) or \(\dim X= \operatorname{ind}X \leq \operatorname{Ind} X\). The second (main) result is a characterization of closed subsets \(X\) of \(\Pi\) having \(\dim X = 1\) and \(\operatorname{ind}X= \operatorname{Ind}X =2\). Let us note that the existence of a closed subset \(X\) of \(\Pi\) with \(\dim X= \operatorname{ind}X< \operatorname{Ind}X\) is an open problem.
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    compactum
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    covering dimension
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    inductive dimensions
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    product
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