
doi: 10.1007/bf02904242
The author continues his paper [Rend. Circ. Mat. Palermo, II. Ser. 45, No. 1, 75-83 (1996; Zbl 0907.54010)], concerning hit-and-miss topologies on the set \(\text{Cl}(X)\) of nonempty closed subsets of a topological space \(X\), taking always closed sets to produce the hit-and-miss basic open sets (\(\Delta\)-topologies). Some known results on first and second countability of the hyperspaces [\textit{G. Di Maio} and \textit{L. Holá}, On hit-and-miss topologies, Rend. Accad. Sci. Fis. Mat., Napoli (4) 62, 103-124 (1995) and with \textit{E. Meccariello}, Rostocker Math. Kolloq. 52, 19-32 (1998; Zbl 0937.54009)] are generalized by dropping assertions on separation properties to weakly-\(R_0\), instead of Hausdorffness or \(T_1\). Furthermore, the author proves, that to be a Tikhonov-space, or completely regular (thus uniformizable), or \(T_3\), or regular, or to have the property \(P_{\Delta}\) with \(\Delta\) being an Uryson family, are all equivalent for the hyperspaces -- without additional requirements to the base space (theorem 2.6). Moreover, it is shown (theorem 2.8), that the following are equivalent for the hyperspaces: metrizability, pseudo-metrizability, to be second countable and regular. The general results are applied especially to Vietoris- and Fell-topology. The reviewer explicitly recommends to read the first part [loc. cit] of this very nice study on \(\Delta\)-topologies, too.
Higher separation axioms (completely regular, normal, perfectly or collectionwise normal, etc.), uniformizability, Metric spaces, metrizability, countability, separation axioms, Hyperspaces in general topology, metrizability
Higher separation axioms (completely regular, normal, perfectly or collectionwise normal, etc.), uniformizability, Metric spaces, metrizability, countability, separation axioms, Hyperspaces in general topology, metrizability
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