activity
20162026
most citedA complete Heyting algebra whose Scott space is non-sober

5 citations · 16 across the 22 of their papers we have counts for

collaborators

23 papers

math.GN2026

Scott--Isbell Coincidence for Continuous Dcpos beyond Bicompleteness

Yuxu Chen, Yunjie Wen, Xiaoyong Xi

Lawson and Mislove posed the following problem in 1990 as Problem~535 in \emph{Open Problems in Topology}: for a core-compact space \(X\) and a dcpo \(P\) equipped with its Scott t…

math.GN2026

Sobriety of Regular Open Algebras in Second-Countable T3 Spaces

Xiaoyong Xi, Chong Shen, Dongsheng Zhao

For a topological space X, let RO(X) be the complete Boolean algebra of regular open subsets of X, ordered by inclusion. We prove that, for every second-countable T3 space X, the S…

math.GN2026

A Quasicontinuous Domain Without an Interval Retract

Chong Shen, Xiaoyong Xi, Dongsheng Zhao

We give negative answers to two questions of X.Xu concerning the occurrence of the unit interval in nonquasialgebraic quasicontinuous domains. We construct, directly from the binar…

math.GN2026

The set of real numbers with the cocountable topology has a bounded complete dcpo model

Dongsheng Zhao, Chong Shen, Xiaoyong Xi

We construct a bounded complete dcpo P whose maximal point space is homeomorphic to the set R of all reals equipped with the cocountable topology, thereby answering an open problem…

math.GN2026

The complete Boolean algebra of regular open sets in real line is not sober

Xiaoyong Xi, Chong Shen, Dongsheng Zhao

Whether the Scott space of the complete Boolean algebra $\RO(\bbR)$ of regular open subsets in the real line is sober was explicitly recorded as an open problem by Xu and Zhao and…

math.GN2026

Scott Function Spaces under One-Sided FS Assumptions: Counterexamples, Positive Results, and New Directions

Chong Shen, Weng Kin Ho, Xiaoyong Xi +1

The class of FS-domains is known to be closed under Scott function spaces when both the source and target are FS-domains. This paper investigates what remains true under one-sided…

math.GN2026

Convergence Choquet-complete spaces and domain representations

Xiaoyong Xi, Chong Shen, Weng Kin Ho +1

de Brecht, Goubault-Larrecq, Jia and Lyu asked whether every sober convergence Choquet-complete space is domain-complete. We introduce the notion of singleton Choquet-completeness,…

math.GN2026

The answers to two problems on dcpo models

Chong Shen, Xiaoyong Xi, Dongsheng Zhao

A poset model of a topological space is a poset such that is homeomorphic to the maximal point space of (the set Max() of all maximal points of equipped with…

math.GN2026

Notes on countable frames

Xiaodong Jia, Xiaoyong Xi

Matthew de Brecht raised the question of whether countable frames are continuous lattices. We prove that the continuity of a countable frame implies the quasicontinuity of its corr…

math.GN2025

The answers to two problems on maximal point spaces of domains

Xiaoyong Xi, Chong Shen, Dongsheng Zhao

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 (with the relative Scott topol…

math.GN2024

Products of two sober dcpo's need not be sober

Hualin Miao, Xiaoyong Xi, Xiaodong Jia +2

We construct two dcpo's whose Scott spaces are sober, but the Scott space of their order product is not sober. This answers an open problem on the sobriety of Scott spaces. Meantim…

math.GN2023

The set of maximal points of an -domain need not be a -set

Gaolin Li, Chong Shen, Kaiyun Wang +2

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

math.GN2022

Further studies on open well-filtered spaces

Chong Shen, Xiaoyong Xi, Dongsheng Zhao

The open well-filtered spaces were introduced by Shen, Xi, Xu and Zhao to answer the problem whether every core-compact well-filtered space is sober. In the current paper we explor…

math.GN2022

On Scott power spaces

Xiaoquan Xu, Xinpeng Wen, Xiaoyong Xi

In this paper, we mainly discuss some basic properties of Scott power spaces. For a space , let be the poset of all nonempty compact saturated subsets of $…

math.GN2022★ 1 cited

Not every countable complete lattice is sober

Hualin Miao, Xiaoyong Xi, Qingguo Li +1

The study of the sobriety of Scott spaces has got an relative long history in domain theory. Lawson and Hoffmann independently proved that the Scott space of every continuous direc…

math.GN2021★ 5 cited

The reflectivity of some categories of T0 spaces in domain theory

Chong Shen, Xiaoyong Xi, Dongsheng Zhao

Keimel and Lawson proposed a set of conditions for proving a category of topological spaces to be reflective in the category of all T0 spaces. These conditions were recently used t…

math.GN2020

-Rudin spaces, well-filtered determined spaces and first-countable spaces

Xiaoquan Xu, Chong Shen, Xiaoyong Xi +1

We investigate some versions of -space, well-filtered space and Rudin space concerning various countability properties. The main results include: (i) if the sobrification of a $…

math.GN2020★ 1 cited

On open well-filtered spaces

Chong Shen, Xiaoyong Xi, Xiaoquan Xu +1

We introduce and study a new class of spaces, called open well-filtered spaces. The main results we proved include (1) every well-filtered space is an open well-filtered spac…

math.GN2019

First countability, -well-filtered spaces and reflections

Xiaoquan Xu, Chong Shen, Xiaoyong Xi +1

We first introduce and study two new classes of subsets in spaces - -Rudin sets and -well-filtered determined sets lying between the class of all closures of countable…

math.GN2019★ 1 cited

On spaces determined by well-filtered spaces

Xiaoquan Xu, Chong Shen, Xiaoyong Xi +1

We first introduce and study two new classes of subsets in spaces - Rudin sets and $\wdd$ sets lying between the class of all closures of directed subsets and that of irreduc…

math.GN2019★ 3 cited

Existence of well-filterifications of topological spaces

Guohua Wu, Xiaoyong Xi, Xiaoquan Xu +1

We prove that for every space , there is a well-filtered space and a continuous mapping $η_X: X\lra W(X)$ such that for any well-filtered space and any continuo…

math.GN2019★ 5 cited

A complete Heyting algebra whose Scott space is non-sober

Xiaoquan Xu, Xiaoyong Xi, Dongsheng Zhao

We prove that (1) for any complete lattice , the set of all nonempty saturated compact subsets of the Scott space of is a complete Heyting algebra (with the…

cs.LO2016

The Ho-Zhao Problem

Weng Kin Ho, Jean Goubault-Larrecq, Achim Jung +1

Given a poset , the set, , of all Scott closed sets ordered by inclusion forms a complete lattice. A subcategory of (the category of posets a…