A rank rigidity result for CAT(0) spaces with one-dimensional Tits boundaries

Abstract

We prove the following rank rigidity result for proper CAT(0) spaces with one-dimensional Tits boundaries: Let $\Gamma$ be a group acting properly discontinuously, cocompactly, and by isometries on such a space $X$. If the Tits diameter of $\partial X$ equals $\pi$ and $\Gamma$ does not act minimally on $\partial X$, then $\partial X$ is a spherical building or a spherical join. If $X$ is also geodesically complete, then $X$ is a Euclidean building, higher rank symmetric space, or a nontrivial product. Much of the proof, which involves finding a Tits-closed convex building-like subset of $\partial X$, does not require the Tits diameter to be $\pi$, and we give an alternate condition that guarantees rigidity when this hypothesis is removed, which is that a certain invariant of the group action be even.

arXiv comment14 pages

References in corpus (5)

• Rank rigidity for CAT(0) cube complexes
• A characterization of irreducible symmetric spaces and Euclidean buildings of higher rank by their asymptotic geometry
• Flat strips, Bowen-Margulis measures, and mixing of the geodesic flow for rank one CAT(0) spaces
• Metric characterizations of spherical, and Euclidean buildings
• Detecting product splittings of CAT(0) spaces

Cited by in corpus (3)

• Rank One Hilbert Geometries
• Extending a rigidity result of Lytchak
• Asymptotic topological regularity of CAT(0) spaces