2 papers
math.GR2026
Density Spectra of Topological Groups
Dekui Peng, Yi Zhou
We study density spectra associated with dense and closed subgroups of topological groups. For a topological group , let $\dd^*(G)$ denote the set of densities of its dense subg…
math.LO2025
The complexity of classifying continuous t-norms up to isomorphism
Jialiang He, Lili Shen, Yi Zhou
It is shown that the isomorphism relation between continuous t-norms is Borel bireducible with the relation of order isomorphism between linear orders on the set of natural numbers…