12 research outputs found
On Completely Separable MAD Families (Set Theory : Reals and Topology)
We survey some constructions of completely separable MAD families
A non-discrete space X with Cp(X) Menger at infinity
[EN] In a paper by Bella, Tokgös and Zdomskyy it is asked whether there exists a Tychonoff space X such that the remainder of Cp(X) in some compactification is Menger but not σ-compact. In this paper we prove that it is consistent that such space exists and in particular its existence follows from the existence of a Menger ultrafilter.The research that led to the present paper was partially supported by a grant of the group GNSAGA of INdAM. The second-named author was also supported by the 2017 PRODEP grant UAM-PTC-636 awarded by the Mexican Secretariat of Public Education (SEP).Bella, A.; Hernández-Gutiérrez, R. (2019). A non-discrete space X with Cp(X) Menger at infinity. Applied General Topology. 20(1):223-230. https://doi.org/10.4995/agt.2019.10714SWORD223230201A. V. Arkhangel'skii, Topological Function Spaces, Mathematics and its Applications (Soviet Series), 78. Kluwer Academic Publishers Group, Dordrecht, 1992. x+205 pp. ISBN: 0-7923-1531-6L. F. Aurichi and A. Bella, When is a space Menger at infinity?, Appl. Gen. Topol. 16, no. 1 (2015), 75-80. https://doi.org/10.4995/agt.2015.3244T. Bartoszynski and H. Judah, Set theory. On the Structure of the Real Line, A K Peters, Ltd., Wellesley, MA, 1995. xii+546 pp. ISBN: 1-56881-044-X https://doi.org/10.1201/9781439863466A. Bella, S. Tokgöz and L. Zdomskyy, Menger remainders of topological groups, Arch. Math. Logic 55, no. 5-6 (2016), 767-784. https://doi.org/10.1007/s00153-016-0493-8D. Chodounsky, D. Repovs and L. Zdomskyy, Mathias forcing and combinatorial covering properties of filters, J. Symb. Log. 80, no. 4 (2015), 1398-1410. https://doi.org/10.1017/jsl.2014.73O. Guzmàn, M. Hrusák and A. Martínez-Celis, Canjar filters, Notre Dame J. Form. Log. 58, no. 1 (2017), 79-95. https://doi.org/10.1215/00294527-3496040M. Henriksen and J. R. Isbell, Some properties of compactifications, Duke Math. J. 25 (1958), 83-105. https://doi.org/10.1215/S0012-7094-58-02509-2R. Hernández-Gutiérrez and P. J. Szeptycki, Some observations on filters with properties defined by open covers, Comment. Math. Univ. Carolin. 56, no. 3 (2015), 355-364. https://doi.org/10.14712/1213-7243.2015.125W. Just, A. W. Miller, M. Scheepers and P. J. Szeptycki, The combinatorics of open covers. II, Topology Appl. 73, no. 3 (1996), 241-266. https://doi.org/10.1016/S0166-8641(96)00075-2W. Marciszewski, P-filters and hereditary Baire function spaces, Topology Appl. 89, no. 3 (1998), 241-247. https://doi.org/10.1016/S0166-8641(97)00216-2W. Marciszewski, On analytic and coanalytic function spaces Cp(X) , Topology Appl. 50 (1993), 341-248. https://doi.org/10.1016/0166-8641(93)90023-7B. Tsaban, Menger's and Hurewicz's problems: solutions from "the book" and refinements, in: Set theory and its applications, 211-226, Contemp. Math., 533, Amer. Math. Soc., Providence, RI, 2011
Games and hereditary Baireness in hyperspaces and spaces of probability measures
We establish that the existence of a winning strategy in certain topological
games, closely related to a strong game of Choquet, played in a topological
space and its hyperspace of all nonempty compact subsets of
equipped with the Vietoris topology, is equivalent for one of the players. For
a separable metrizable space , we identify a game-theoretic condition
equivalent to being hereditarily Baire. It implies quite easily a recent
result of Gartside, Medini and Zdomskyy that characterizes hereditary Baire
property of hyperspaces over separable metrizable spaces via the
Menger property of the remainder of a compactification of . Subsequently, we
use topological games to study hereditary Baire property in spaces of
probability measures and in hyperspaces over filters on natural numbers. To
this end, we introduce a notion of strong -filter and prove
that it is equivalent to being hereditarily Baire. We also
show that if is separable metrizable and is hereditarily Baire, then
the space of Borel probability Radon measures on is hereditarily
Baire too. It follows that there exists (in ZFC) a separable metrizable space
which is not completely metrizable with hereditarily Baire. As far
as we know this is the first example of this kind