2 papers
math.GN2026
The descriptive complexity of the set of arc-connected compact subsets of the plane
Gabriel Debs, Jean Saint Raymond
We compute the exact complexity of the set of all arc-connected compact subsets of $\boldmath R^2$, which turns out to be strictly higher than the classical $\boldmath Σ^1_1$ and $…
math.LO2018
The descriptive complexity of the set of all closed zero-dimensional subsets of a Polish space
Gabriel Debs, Jean Saint Raymond
Given a space we investigate the descriptive complexity class $\G_X$ of the set $\FF_0(X)$ of all its closed zero-dimensional subsets, viewed as a subset of the hyperspace $\FF…