2 citations · 3 across the 2 of their papers we have counts for
4 papers
On the Pettis-Johnstone theorem for localic groups
Ruiyuan Chen
We explain how Johnstone's 1989 proof of the closed subgroup theorem for localic groups can be viewed as a point-free version of Pettis's theorem for Baire topological groups. We t…
Borel and analytic sets in locales
Ruiyuan Chen
We systematically develop analogs of basic concepts from classical descriptive set theory in the context of pointless topology. Our starting point is to take the elements of the fr…
Representing Polish groupoids via metric structures
Ruiyuan Chen
We prove that every open -locally Polish groupoid is Borel equivalent to the groupoid of models on the Urysohn sphere of an -sentence in con…
Bounds on Continuous Scott Rank
William Chan, Ruiyuan Chen
An analog of Nadel's effective bound for the continuous Scott rank of metric structures, developed by Ben Yaacov, Doucha, Nies, and Tsankov, will be established: Let …