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ON R-COMPACT SPACES

On \(R\)-compact spaces
Authors: CAMMAROTO, Filippo; TAKASHI NOIRI;

ON R-COMPACT SPACES

Abstract

Let \(\mathcal U\) and \(\mathcal V\) be open covers of a space \(X\). \(\mathcal V\) is a shrinkable refinement of \(\mathcal U\) [the reviewer with \textit{M. P. Berri} and \textit{R. M. Stephenson jun.}, Proc. Kanpur Topol. Conf. 1968, 93--114 (1971; Zbl 0235.54018)] if for each \(V\in{\mathcal V}\), there is a \(U\in{\mathcal U}\) such that \(\text{cl }V\subseteq U\). A space is \(U(i)\) or quasi-\(U\)-closed [\textit{C. T. Scarborough}, Pac. J. Math. 27, 611--617 (1968; Zbl 0189.23104)] if every open cover with shrinkable refinement has a finite subfamily whose closures cover. The authors introduce the concept of \(R\)-compactness; a space is \(R\)-compact if every open cover with shrinkable refinement has a finite subcover. It follows that a quasi-\(H\)-closed space is \(R\)-compact and an \(R\)-compact space is quasi-\(U\)-closed. Many characterizations and some mapping results of \(R\)-compact are obtained.

Related Organizations
Keywords

quasi-\(H\)-closed space, Compactness, ``\(P\)-minimal'' and ``\(P\)-closed'' spaces, almost compact space

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
0
Average
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