English

On balanced coronas of groups

General Topology 2019-05-20 v1

Abstract

Let GG be an infinite group, κ\kappa be an infinite cardinal, κG\kappa\leq \mid G\mid and let Eκ\mathcal{E}_{\kappa} denotes a coarse structure on GG with the base {{(x,y):yFxF}:F[G]<κ}\{\{ (x,y): y\in F x F\}: F\in [G]^{<\kappa}\}. We prove that if either κ<G\kappa< \mid G\mid or κ=G\kappa= \mid G\mid and κ\kappa is singular then the Higson's corona νκ(G)\nu _{\kappa} (G) of the coarse space (G,Eκ)(G, \mathcal{E}_{\kappa}) is a singleton. If κ=G\kappa= \mid G\mid and κ\kappa is regular then νκ(G)\nu _{\kappa} (G) contains a copy of the space UκU_{\kappa} of κ\kappa-uniform ultrafilters on κ\kappa.

Keywords

Cite

@article{arxiv.1905.07142,
  title  = {On balanced coronas of groups},
  author = {Igor Protasov},
  journal= {arXiv preprint arXiv:1905.07142},
  year   = {2019}
}

Comments

coarse structure, slowly oscillating functions, balanced corona

R2 v1 2026-06-23T09:10:15.116Z