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Coincidence of the upper Kuratowski topology with the co-compact topology on compact sets, and the Prohorov property
Bouziad, Ahmed
HAL, hal-00373418 / Harvested from HAL
For a Hausdorff space $X$, let $ F$ be the hyperspace of all closed subsets of X and $H$ a sublattice of $ F$. Following Nogura and Shakhmatov, $X$ is said to be $H$-trivial if the upper Kuratowski topology and the co-compact topology coincide on $H$. $F$-trivial spaces are the consonant spaces first introduced and studied by Dolecki, Greco and Lechicki. In this paper, we deal with $K$-trivial spaces and Fin-trivial space, where $K$ and Fin are respectively the lattices of compact and of finite subsets of $X$. It is proved that if $C_k(X)$ is a Baire space or more generally if $X$ has ‘the moving off property' of Gruenhage and Ma, then $X$ is $K$-trivial. If $X$ is countable, then $C_p(X)$ is Baire if and only if $X$ is Fin-trivial and all compact subsets of $X$ are finite. As for consonant spaces, it turns out that every regular $K$-trivial space is a Prohorov space. This result remains true for any regular Fin-trivial space in which all compact subsets are scattered. It follows that every regular first countable space without isolated points, all compact subsets of which are countable, is Fin-nontrivial. Examples of $K$-trivial non-consonant spaces, of Fin-trivial $K$-nontrivial spaces and of countably compact Prohorov Finnontrivial spaces, are given. In particular, we show that all (generalized) Fréchet-Urysohn fans are $K$-trivial, answering a question by Nogura and Shakhmatov. Finally, we describe an example of a continuous open compact-covering mapping $f :X\to Y$, where $X$ is Prohorov and $Y$ is not Prohorov, answering a long-standing question by Topsøe.
Publié le : 2002-07-05
Classification:  Hyperspaces,  Upper Kuratowski convergence,  Co-compact topology,  Radon measure,  Prohorov spaces,  54B20; 54C35; 28A05; 28C15,  [MATH.MATH-GN]Mathematics [math]/General Topology [math.GN]
@article{hal-00373418,
     author = {Bouziad, Ahmed},
     title = {Coincidence of the upper Kuratowski topology with the co-compact topology on compact sets, and the Prohorov property},
     journal = {HAL},
     volume = {2002},
     number = {0},
     year = {2002},
     language = {en},
     url = {http://dml.mathdoc.fr/item/hal-00373418}
}
Bouziad, Ahmed. Coincidence of the upper Kuratowski topology with the co-compact topology on compact sets, and the Prohorov property. HAL, Tome 2002 (2002) no. 0, . http://gdmltest.u-ga.fr/item/hal-00373418/