Measured groupoids beyond equivalence relations and group actions
arXiv:2410.15147
Abstract
We construct the first examples of genuine ergodic discrete measured groupoids that are not isomorphic to any equivalence relation or transformation groupoid. We use a construction due to B.H. Neumann of an uncountable family of pairwise non-isomorphic 2-generated groups for our result.
v2, minor changes; to appear in Groups, Geometry and Dynamics