collaborators

6 papers

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

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

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.GN2025

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.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…