English

Bounded orbits and global fixed points for groups acting on the plane

Dynamical Systems 2014-10-01 v2 Geometric Topology

Abstract

Let G be a group acting on the plane by orientation-preserving homeomorphisms. We show that if for some k>0 there is a ball of radius r > k/\sqrt{3} such that each point x in the ball satisfies |gx -hx| < k for all g, h in G, and the action of G satisfies a nonwandering hypothesis, then the action has a global fixed point. In particular, any group of measure-preserving orientation preserving homeomorphisms of the plane with uniformly bounded orbits has a global fixed point. The constant k/\sqrt{3} is sharp. We also show that a group acting on the plane with orbits bounded as above is left orderable.

Keywords

Cite

@article{arxiv.1103.5060,
  title  = {Bounded orbits and global fixed points for groups acting on the plane},
  author = {Kathryn Mann},
  journal= {arXiv preprint arXiv:1103.5060},
  year   = {2014}
}

Comments

v2 reflects published version. Added argument in section 2, results unchanged

R2 v1 2026-06-21T17:44:44.860Z