中文
相关论文

相关论文: The projectively Hurewicz property is t-invariant

200 篇论文

For a Tychonoff space $X$, we denote by $C_p(X)$ the space of all real-valued continuous functions on $X$ with the topology of pointwise convergence. We give the functional characterization of the covering property of Hurewicz.

一般拓扑 · 数学 2018-05-31 Alexander V. Osipov

In this paper, we introduced the mildly version of the Hurewicz basis covering property, studied by Babinkostova, Ko\v{c}inac, and Scheepers. A space $X$ is said to have mildly-Hurewicz property if for each sequence $\langle \mathcal{U}_n :…

一般拓扑 · 数学 2022-02-28 Manoj Bhardwaj , Alexander V. Osipov

We prove that assuming $\mathfrak{b}=\mathfrak{d}$, in the class of hereditarily Lindel\"of spaces, each productively Scheepers space is productively Hurewicz. The above statement remains true in the class of all general topological spaces…

一般拓扑 · 数学 2026-02-19 Marta Kładź-Duda , Piotr Szewczak , Lyubomyr Zdomskyy

A classical theorem of Hurewicz characterizes spaces with the Hurewicz covering property as those having bounded continuous images in the Baire space. We give a similar characterization for spaces X which have the Hurewicz property…

一般拓扑 · 数学 2014-09-02 Boaz Tsaban , Lyubomyr Zdomskyy

In this paper, we introduced $\alpha$-Hurewicz $\&$ $\theta$-Hurewicz properties in a topological space $X$ and investigated their relationship with other selective covering properties. We have shown that for an extremally disconnected…

一般拓扑 · 数学 2023-07-04 Gaurav Kumar , Sumit Mittal , Brij K. Tyagi

We characterize the Hurewicz covering property in metrizable spaces in terms of properties of the metrics of the space. Then we show that a weak version of selective screenability, when combined with the Hurewicz property, implies selective…

一般拓扑 · 数学 2007-12-10 Liljana Babinkostova

It is known that both the Menger and Hurewicz property of a Tychonoff space $X$ can be described by the way $X$ is placed in its \v{C}ech-Stone compactification $\beta X$. We provide analogous characterizations for the projective versions…

一般拓扑 · 数学 2024-05-08 Mikołaj Krupski , Kacper Kucharski

Let $X$ be metrizable, $Y$ be perfectly normal and suppose that there exists a uniformly continuous surjection $T: C_{p}(X) \to C_{p}(Y)$ (resp., $T: C_{p}^*(X) \to C_{p}^*(Y)$), where $C_{p}(X)$ (resp., $C_{p}^*(X)$) denotes the space of…

一般拓扑 · 数学 2025-05-06 A. Eysen , A. Leiderman , V. Valov

We prove a new selection theorem for multivalued mappings of C-space. Using this theorem we prove extension dimensional version of Hurewicz theorem for a closed mapping $f\colon X\to Y$ of $k$-space $X$ onto paracompact $C$-space $Y$: if…

代数拓扑 · 数学 2007-05-23 N. Brodsky , A. Chigogidze

For an $\A^1$-connected pointed simplicial sheaf $\sX$ over a perfect field $k$, we prove that the Hurewicz map $\pi_1^{\A^1}(\sX) \to H_1^{\A^1}(\sX)$ is surjective. We also observe that the Hurewicz map for $\P^1_k$ is the abelianisation…

代数几何 · 数学 2022-06-22 Utsav Choudhury , Amit Hogadi

Let $\mathcal{P}$ be a topological property. A.V. Arhangel'skii calls $X$ projectively $\mathcal{P}$ if every second countable continuous image of $X$ is $\mathcal{P}$. Lj.D.R. Ko$\check{c}$inac characterized the classical covering…

一般拓扑 · 数学 2020-05-06 Alexander V. Osipov

All spaces are assumed to be separable and metrizable. Consider the following properties of a space $X$. (1) $X$ is Polish. (2) For every countable crowded $Q\subseteq X$ there exists a crowded $Q'\subseteq Q$ with compact closure. (3)…

一般拓扑 · 数学 2014-06-02 Andrea Medini , Lyubomyr Zdomskyy

We prove that for each Polish space X, the space C(X) of continuous real-valued functions on X satisfies a strong version of the Pytkeev property, if endowed with the compact-open topology. (This shows that whereas it need not be…

一般拓扑 · 数学 2010-11-05 Boaz Tsaban , Lyubomyr Zdomskyy

For a completely regular space $X$, denote by $C_p(X)$ the space of continuous real-valued functions on $X$, with the pointwise convergence topology. In this article we strengthen a theorem of O. Okunev concerning preservation of some…

一般拓扑 · 数学 2023-09-28 Mikolaj Krupski

We prove that under certain set-theoretic assumptions every productively Lindel\"of space has the Hurewicz covering property, thus improving upon some earlier results of Aurichi and Tall.

一般拓扑 · 数学 2014-06-04 Dušan Repovš , Lyubomyr Zdomskyy

We prove that if X is a separable metric space with the Hurewicz covering property, then the Banach-Mazur game played on X is determined. The implication is not true when "Hurewicz covering property" is replaced with "Menger covering…

一般拓扑 · 数学 2007-11-08 Marion Scheepers

In this paper, we continue to investigate topological properties of $\mathcal{I}H$ and its two star versions namely $SS \mathcal{I} H$ and $S \mathcal{I} H$. We characterized $\mathcal{I}$-Hurewicz property by $\mathcal{I}$-Hurewicz Basis…

一般拓扑 · 数学 2019-10-31 Manoj Bhardwaj , B. K. Tyagi

We give an example of an infinite metrizable space $X$ such that the space $C_p(X)$, of continuous real-valued function on $X$ endowed with the pointwise topology, is not homeomorphic to its own square $C_p(X)\times C_p(X)$. The space $X$…

一般拓扑 · 数学 2018-12-12 Mikołaj Krupski , Witold Marciszewski

We recall a characterization of hereditary indecomposability originally obtained by Krasinkiewicz and Minc, and show how it may be used to give unified constructions of various hereditarily indecomposable continua. In particular we answer a…

一般拓扑 · 数学 2007-05-23 Klaas Pieter Hart , Jan van Mill , Roman Pol

In this paper we develop a technique of constructing uni- formly continuous maps between function spaces Cp(X) endowed with the pointwise topology. We prove that if a space X is compact metrizable and strongly countable-dimensional, then…

一般拓扑 · 数学 2017-10-31 Rafal Gorak , Mikolaj Krupski , Witold Marciszewski
‹ 上一页 1 2 3 10 下一页 ›