Dynamics of flat actions on totally disconnected, locally compact groups
arXiv:1503.01863
Abstract
Let be a totally disconnected, locally compact group and let be a virtually flat (for example, polycyclic) group of automorphisms of . We study the structure of, and relationships between, various subgroups of defined by the dynamics of . In particular, we consider the following four subgroups: the intersection of all tidy subgroups for on (in the case that is flat); the intersection of all -invariant open subgroups of ; the smallest closed -invariant subgroup such that no -orbit on accumulates at the trivial coset; and the group generated by the closures of contraction groups of elements of on .
81 pages; accepted version. Final published version is here: http://nyjm.albany.edu/j/2016/22-6.html