3 papers
math.OA2026
Boundary actions of Bass-Serre Trees and the applications to -algebras
Xin Ma, Daxun Wang, Wenyuan Yang
In this paper, we study Bass-Serre theory from the perspectives of -algebras and topological dynamics. In particular, we investigate the actions of fundamental groups of graph…
math.DS2026
Ample groupoids that are neither almost finite nor purely infinite
Xiaolei Wu, Mengfei Zhao, Xin Ma
We study a question of Matui and varations of it on minimal ample groupoids that are neither almost finite nor purely infinite. We first observe that there are already effective mi…
math.GR2025
Boundary actions of CAT(0) spaces: topological freeness and applications to -algebras
Xin Ma, Daxun Wang, Wenyuan Yang
In this paper, we study topological dynamics on the visual boundary and several combinatorial boundaries associated to spaces. Through verifying the freenes…