A hyperbolic group without a geometric CAT(0) action
What the paper claims, in its own words
Answers negatively whether every word-hyperbolic group is a CAT(0) group. Constructs one with a finite classifying space but no proper cocompact isometric action on any proper complete space, in any dimension.
The plain-language explainer for this entry is still coming.
The original paper
- A hyperbolic group with no geometric CAT(0) action (PDF, opens in a new tab) September 25, 2026 Formal proof listed