English

At infinity of finite-dimensional CAT(0) spaces

Group Theory 2014-05-16 v2 Metric Geometry

Abstract

We show that any filtering family of closed convex subsets of a finite-dimensional CAT(0) space XX has a non-empty intersection in the visual bordification Xˉ=XX \bar{X} = X \cup \partial X. Using this fact, several results known for proper CAT(0) spaces may be extended to finite-dimensional spaces, including the existence of canonical fixed points at infinity for parabolic isometries, algebraic and geometric restrictions on amenable group actions, and geometric superrigidity for non-elementary actions of irreducible uniform lattices in products of locally compact groups.

Keywords

Cite

@article{arxiv.0810.2895,
  title  = {At infinity of finite-dimensional CAT(0) spaces},
  author = {Pierre-Emmanuel Caprace and Alexander Lytchak},
  journal= {arXiv preprint arXiv:0810.2895},
  year   = {2014}
}

Comments

An erratum filling in a gap in the proof of an application of the main result has been included to the original paper

R2 v1 2026-06-21T11:31:25.414Z