Actions of discrete groups on stationary Lorentz manifolds
The authors study the geometry of compact Lorentzian manifolds that admit a somewhere time-like Killing vector field, and whose isometry group is non-compact (for having an infinite number of connected components). Up to a finite cover, such manifolds are products (resp. amalgamated products) of a flat Lorentzian torus and a compact Riemannian (resp. light-like) manifold.
scientific article; zbMATH DE number 6366534