Conjugacy equivalence relation on subgroups
Volume 167 / 2001
Fundamenta Mathematicae 167 (2001), 189-212
MSC: 03E15, 20E05, 20F05.
DOI: 10.4064/fm167-3-1
Abstract
If $G$ is a countable group containing a copy of ${\bf F}_2$ then the conjugacy equivalence relation on subgroups of $G$ attains the maximal possible complexity.
