English

On minimal flows and definable amenability in some distal NIP theories

Logic 2023-02-14 v2

Abstract

We study the definable topological dynamics (G(M),SG(M))(G(M), S_G(M)) of a definable group acting on its type space, where MM is either an oo-minimal structure or a pp-adically closed field, and GG a definable amenable group. We focus on the problem raised by Neweslki of whether weakly generic types coincide with almost periodic types, showing that the answer is positive when GG has boundedly many global weakly generic types. We also give two "minimal counterexamples" where GG has unboundedly many global weakly generic types, extending the main results of "On minimal flows, definably amenable groups, and o-minimality" to a more general context.

Keywords

Cite

@article{arxiv.2209.08495,
  title  = {On minimal flows and definable amenability in some distal NIP theories},
  author = {Ningyuan Yao and Zhentao Zhang},
  journal= {arXiv preprint arXiv:2209.08495},
  year   = {2023}
}