Ziqin Feng

activity

20232025

collaborators

3 papers

math.GN2025

The Shape of Generating Families

Ziqin Feng, Paul Gartside

The topology of a space $X$ is generated by a family $C$ of its subsets provided that a set $A \subseteq X$ is closed in $X$ if and only if $A \cap C$ is closed in $C$ for…

math.GN2024

The Shape of Compact Covers

Ziqin Feng, Paul Gartside

For a space $X$ let $K (X)$ be the set of compact subsets of $X$ ordered by inclusion. A map $ϕ : K (X) \to K (Y)$ is a relative Tukey quotient if it carri…

math.GN2023

Directed Sets of Topology -- Tukey Representation and Rejection

Ziqin Feng, Paul Gartside

Every directed set is Tukey equivalent to (a) the family of all compact subsets, ordered by inclusion, of a (locally compact) space, to (b) a neighborhood filter, ordered by revers…