hsfzLZH1's Homepage
2026
- Recognizing polycyclic groups from their large-scale shape
- Solving independent equations without collapsing the coefficient group
- A hyperbolic group that cannot act geometrically on a CAT(0) space
- One relation, negative curvature, and finite special covers
- The same group can have actions with different costs
- Continuous symmetries of manifolds must form Lie groups
- Four-dimensional disk embedding and a duality group with no manifold model
- A nontrivial knot remembers its surgery slope
- Finite spectra that remove the first chromatic parameters
- Large-scale topology can disappear under coarse assembly