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Mazurkiewicz manifolds and homogeneity - MaRDI portal

Mazurkiewicz manifolds and homogeneity (Q658378)

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Mazurkiewicz manifolds and homogeneity
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    Mazurkiewicz manifolds and homogeneity (English)
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    12 January 2012
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    This paper deals with metrizable spaces \(X\). Let \(\mathcal{C}\) be a class of spaces. One says that \(X\) is a Cantor manifold with respect to \(\mathcal{C}\) if \(X\) cannot be separated by a closed subset that belongs to \(\mathcal{C}\). It is called a Mazurkiewicz manifold with respect to \(\mathcal{C}\) if for every two closed disjoint subsets \(X_0\), \(X_1\) of \(X\), both having non-empty interiors in \(X\), and every \(F_\sigma\)-subset \(F\) of \(X\) with \(F\in\mathcal{C}\), there exists a continuum in \(X\setminus F\) joining \(X_0\) and \(X_1\). It is noted that each Mazurkiewicz manifold with respect to \(\mathcal{C}\) is a Cantor manifold with respect to \(\mathcal{C}\). The idea is to select \(\mathcal{C}\) from among \(\{\mathcal{WID} ,\mathbb{C},\mathcal{D}_{\mathcal{K}}^{n-2},\mathcal{D}_{\mathcal{K}}^\infty\}\). For example, \(\mathcal{WID}\) is the class of weakly infinite-dimensional spaces and \(\mathbb{C}\) is the class of \(C\)-spaces. Definitions of the two others may be found on page 1934. The main theorem is: \textbf{Theorem 4.} Let \(X\) be a homogeneous locally compact, locally connected metric space. Suppose \(U\) is a region in \(X\) and \(U\notin\mathcal{C}\), \(\mathcal{C}\in \{\mathcal{WID} ,\mathbb{C},\mathcal{D}_{\mathcal{K}}^{n-2},\mathcal{D}_{\mathcal{K}}^\infty\}\). In case \(C=\mathcal{D}_{\mathcal{K}}^{n-2}\), assume that \(\mathcal{D}_{\mathcal{K}}(U)=n\). Then \(U\) is a Mazurkiewicz manifold with respect to \(\mathcal{C}\).
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    Cantor manifold
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    Mazurkiewicz manifold, cohomological dimension
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    \(C\)-space
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    strongly infinite dimensional
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    covering dimension
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    homogeneous space
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