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Continuous selections and \(\sigma \)-spaces - MaRDI portal

Continuous selections and \(\sigma \)-spaces (Q958510)

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Continuous selections and \(\sigma \)-spaces
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    Continuous selections and \(\sigma \)-spaces (English)
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    5 December 2008
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    It is proved that \(X\) is a space in which \(F_\sigma\)-sets are simultaneously \(G_\delta\)-sets (a \(\sigma\)-space) if and only if each lower-semicontinuous multifunction defined on \(X\) and with values being closed-open subsets of a space homeomorphic to the space of rational numbers admits a continuous selection. Then connections with the Sheepers conjecture are explained and two open questions are posed.
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    multifunction
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    continuous selection
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    \(b\)-scale
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    lower-semicontinuity
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    Fréchet filter
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    Sheepers conjecture
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