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Fréchet-Urysohn for finite sets, II (Q2381641)

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Fréchet-Urysohn for finite sets, II
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    Fréchet-Urysohn for finite sets, II (English)
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    18 September 2007
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    This paper continues the study begun in [Topology Appl. 151, 238--259 (2005; Zbl 1085.54016)]. It is established that there exists a space which is Fréchet \(\alpha _2\) but not Fréchet-Urysohn for 2-point sets and hence not \(FU_{\text{fin}}\) answering a question posed in the paper cited above. The example relates to a Hausdorff gap space. The paper also extends relationships of \(FU_{\text{fin}}\) with ``selection principles'' , topological games, and the \(\alpha_i\)-spaces introduced by Arhangel'skii.
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    Fréchet-Urysohn
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    gap spaces
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    \(\alpha_i\)-spaces
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    \(\pi\)-network
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