English
Related papers

Related papers: Xi-Zhao Model Preserves WD Spaces

200 papers

In this paper, we highlight some open problems stated by Xu and Zhao. In particular, we focus on strong $d$-spaces and answer two open problems concerning strong $d$-spaces. One is about the product space of an arbitrary family of strong…

General Topology · Mathematics 2021-09-24 Mengjie Jin , Hualin Miao , Qingguo Li

In this paper, we provide a uniform approach to $d$-spaces, sober spaces and well-filtered spaces, and develop a general framework for dealing with all these spaces. For a subset system H, the theory of H-sober spaces and super H-sober…

General Topology · Mathematics 2020-03-18 Xiaoquan Xu

In this paper, we obtain some sufficient conditions for the D-completion of a T0 space to be the well-filterification of this space, the well-filterification of a T0 space to be the sobrification of this space and the D-completion of a T0…

General Topology · Mathematics 2021-01-14 Hualin Miao , Longchun Wang , Qingguo Li

Recently, Xu proposed a strongly well-filtered space in [24] and systematically investigated some of its properties and characterizations. In this paper, we introduce a new class of T0-spaces called S*-well-filtered spaces, which is…

General Topology · Mathematics 2026-01-19 Nana Han , Siheng Chen , Qingguo Li

We prove that for every $T_0$ space $X$, there is a well-filtered space $W(X)$ and a continuous mapping $\eta_X: X\lra W(X)$ such that for any well-filtered space $Y$ and any continuous mapping $f: X\lra Y$ there is a unique continuous…

General Topology · Mathematics 2019-07-16 Guohua Wu , Xiaoyong Xi , Xiaoquan Xu , Dongsheng Zhao

A topological space has a domain model if it is homeomorphic to the maximal point space $\mbox{Max}(P)$ of a domain $P$. Lawson proved that every Polish space $X$ has an $\omega$-domain model $P$ and for such a model $P$, $\mbox{Max}(P)$ is…

General Topology · Mathematics 2023-05-09 Gaolin Li , Chong Shen , Kaiyun Wang , Xiaoyong Xi , Dongsheng Zhao

We first introduce and study two new classes of subsets in $T_0$ spaces - Rudin sets and $\wdd$ sets lying between the class of all closures of directed subsets and that of irreducible closed subsets. Using such subsets, we define three new…

General Topology · Mathematics 2019-09-23 Xiaoquan Xu , Chong Shen , Xiaoyong Xi , Dongsheng Zhao

In this paper, we will focus on k-bounded sober spaces and show the existence of a T_0 space X not admitting any k-bounded sobrification. This strengthens a result of Zhao, Lu and Wang, who proved that the canonical k-bounded sobrification…

General Topology · Mathematics 2020-11-24 Jing Lu , Kaiyun Wang , Guohua Wu , Bin Zhao

Inspired by Zhao and Xu's study on which a dcpo can be determined by its Scott closed subsets lattice, we further investigate whether a poset (or dcpo) $P$ is able to be determined by the family $\mathcal Q(P)$ of its Scott compact…

General Topology · Mathematics 2025-03-05 Huijun Hou , Qingguo Li

A topological space is domain-representable (or, has a domain model) if it is homeomorphic to the maximal point space $\mbox{Max}(P)$ of a domain $P$ (with the relative Scott topology). We first construct an example to show that the set of…

General Topology · Mathematics 2025-02-27 Xiaoyong Xi , Chong Shen , Dongsheng Zhao

A non-empty subset of a topological space is irreducible if whenever it is covered by the union of two closed sets, then already it is covered by one of them. Irreducible sets occur in proliferation: (1) every singleton set is irreducible,…

Logic in Computer Science · Computer Science 2016-10-04 Hadrian Andradi , Weng Kin Ho

We first introduce and investigate a new class of $T_0$ spaces -- strong R-spaces, which are stronger than both R-spaces and strongly well-filtered spaces. It is proved that any sup-complete poset equipped with the upper topology is a…

General Topology · Mathematics 2025-12-12 Xiaoquan Xu , Yi Yang , Lizi Chen

We prove that a $T_0$ topological space is $\omega$-well-filtered if and only if it does not admit either the natural numbers with the cofinite topology or with the Scott topology as its closed subsets in the strong topology. Based on this,…

General Topology · Mathematics 2024-09-04 Hualin Miao , Xiaodong Jia , Ao Shen , Qingguo Li

Let ${\mathscr P}$ be a topological property. We say that a space $X$ is ${\mathscr P}$-connected if there exists no pair $C$ and $D$ of disjoint cozero-sets of $X$ with non-${\mathscr P}$ closure such that the remainder $X\backslash(C\cup…

General Topology · Mathematics 2015-06-26 M. R. Koushesh

Recently, J. D. Lawson encouraged the domain theory community to consider the scientific program of developing domain theory in the wider context of $T_0$-spaces instead of restricting to posets. In this paper, we respond to this calling by…

Logic in Computer Science · Computer Science 2017-09-12 Hadrian Andradi , Weng Kin Ho

Given a finite poset $\mathcal P$, the hypercube-height, denoted by $h^*(\mathcal P)$, is defined to be the largest $h$ such that, for any natural number $n$, the subsets of $[n]$ of size less than $h$ do not contain an induced copy of…

Combinatorics · Mathematics 2025-10-01 Tomáš Flídr , Maria-Romina Ivan , Sean Jaffe

Let $X$ be an unbounded metric space, $B(x,r) = \{y\in X: d(x,y) \leqslant r\}$ for all $x\in X$ and $r\geqslant 0$. We endow $X$ with the discrete topology and identify the Stone-\v{C}ech compactification $\beta X$ of $X$ with the set of…

General Topology · Mathematics 2013-10-10 I. V. Protasov

We first introduce and study two new classes of subsets in $T_0$ spaces - $\omega$-Rudin sets and $\omega$-well-filtered determined sets lying between the class of all closures of countable directed subsets and that of irreducible closed…

General Topology · Mathematics 2019-12-02 Xiaoquan Xu , Chong Shen , Xiaoyong Xi , Dongsheng Zhaod

For a locally pseudocompact space $X$ let [\zeta X=X\cup cl_{\beta X}(\beta X\backslash\upsilon X).] It is proved that $\zeta X$ is the largest (with respect to the standard partial order $\leq$) among all pseudocompactifications of $X$…

General Topology · Mathematics 2015-06-26 M. R. Koushesh

It is well-known that a metric space $(X, d)$ is complete iff the set $X$ is closed in every metric superspace of $(X, d)$. For a given pseudometric space $(Y, \rho)$, we describe the maximal class $\mathbf{CEC}(Y, \rho)$ of superspaces of…

General Topology · Mathematics 2022-06-06 Viktoriia Bilet , Oleksiy Dovgoshey
‹ Prev 1 2 3 10 Next ›