scholarly journals Selection principles and games in bitopological function spaces

Filomat ◽  
2019 ◽  
Vol 33 (14) ◽  
pp. 4535-4540
Author(s):  
Daniil Lyakhovets ◽  
Alexander Osipov

For a Tychonoff space X, we denote by (C(X), ?k ?p) the bitopological space of all real-valued continuous functions on X, where ?k is the compact-open topology and ?p is the topology of pointwise convergence. In the papers [6, 7, 13] variations of selective separability and tightness in (C(X),?k,?p) were investigated. In this paper we continue to study the selective properties and the corresponding topological games in the space (C(X),?k,?p).

Filomat ◽  
2018 ◽  
Vol 32 (15) ◽  
pp. 5403-5413 ◽  
Author(s):  
Alexander Osipov

For a Tychonoff space X, we denote by Ck(X) the space of all real-valued continuous functions on X with the compact-open topology. A subset A ? X is said to be sequentially dense in X if every point of X is the limit of a convergent sequence in A. In this paper, the following properties for Ck(X) are considered. S1(S,S)=> Sfin(S,S) => Sfin(S,D) <=S1(S,D) S1(D,S) => Sfin(D,S) => Sfin(D,D) <= S1(D,D) For example, a space Ck(X) satisfies S1(S,D) (resp., Sfin(S,D)) if whenever (Sn : n ? N) is a sequence of sequentially dense subsets of Ck(X), one can take points fn ? Sn (resp., finite Fn ? Sn) such that {fn : n ? N} (resp.,U {Fn : n ? Ng) is dense in Ck(X). Other properties are defined similarly. In [22], we obtained characterizations these selection properties for Cp(X). In this paper, we give characterizations for Ck(X).


Author(s):  
R. A. McCoy

A study is made of the properties onXwhich characterize whenCπ(X)is ak-space, whereCπ(X)is the space of real-valued continuous functions onXhaving the topology of pointwise convergence. Other properties related to thek-space property are also considered.


2021 ◽  
Vol 78 (1) ◽  
pp. 199-214
Author(s):  
Lev Bukovský

Abstract The paper tries to survey the recent results about relationships between covering properties of a topological space X and the space USC(X) of upper semicontinuous functions on X with the topology of pointwise convergence. Dealing with properties of continuous functions C(X), we need shrinkable covers. The results are extended for A-measurable and upper A-semimeasurable functions where A is a family of subsets of X. Similar results for covers respecting a bornology and spaces USC(X) or C(X) endowed by a topology defined by using the bornology are presented. Some of them seem to be new.


2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Juan Carlos Ferrando

We characterize in terms of the topology of a Tychonoff space X the existence of a bounded resolution for CcX that swallows the bounded sets, where CcX is the space of real-valued continuous functions on X equipped with the compact-open topology.


2003 ◽  
Vol 4 (2) ◽  
pp. 509 ◽  
Author(s):  
Wladyslaw Wilczynski

<p>We shall show that the space of all approximately continuous functions with the topology of pointwise convergence is not homeomorphic to its category analogue.</p>


2003 ◽  
Vol 80 (6) ◽  
pp. 655-663 ◽  
Author(s):  
Jan van Mill ◽  
Jan Pelant ◽  
Roman Pol

2003 ◽  
Vol 4 (2) ◽  
pp. 255 ◽  
Author(s):  
Ljubisa D.R. Kocinac

<p>In this paper we investigate some closure properties of the space Ck(X) of continuous real-valued functions on a Tychonoff space X endowed with the compact-open topology.</p>


2019 ◽  
Vol 69 (3) ◽  
pp. 699-706 ◽  
Author(s):  
Alexander V. Osipov

Abstract For a Tychonoff space X and a family λ of subsets of X, we denote by Cλ(X) the space of all real-valued continuous functions on X with the set-open topology. A Menger space is a topological space in which for every sequence of open covers 𝓤1, 𝓤2, … of the space there are finite sets 𝓕1 ⊂ 𝓤1, 𝓕2 ⊂ 𝓤2, … such that family 𝓕1 ∪ 𝓕2 ∪ … covers the space. In this paper, we study the Menger and projective Menger properties of a Hausdorff space Cλ(X). Our main results state that Cλ(X) is Menger if and only if Cλ(X) is σ-compact; Cp(Y | X) is projective Menger if and only if Cp(Y | X) is σ-pseudocompact where Y is a dense subset of X.


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