3 papers
math.LO2026
The epimorphism relation among countable groups is a complete analytic quasi-order
Su Gao, Feng Li, André Nies +1
We prove that the epimorphism relation is a complete analytic quasi-order on the space of countable groups. In the process, we obtain the result of independent interest that the ep…
math.LO2026
Extremely amenable automorphism groups of countable structures
Mahmood Etedadialiabadi, Su Gao, Feng Li +1
In this paper we address the question: How many pairwise non-isomorphic extremely amenable groups are there which are separable metrizable or even Polish? We show that there are co…
math.LO2025
On the Isomorphism Relation for Omnigenous Locally Finite Groups
Su Gao, Feng Li
The concept of an omnigenous locally finite group was introduced in [2] as a generalization of Hall's universal countable locally finite group. In this paper we show that the class…