2006/01/09 by Mohamed Deffaf, Deffaf, Mohamed, Karin Melnick +3
Mathematics · #37C85 #53A35 #57S20 #Advanced Operator Algebra Research #Differential Geometry (math.DG) #Dynamical Systems (math.DS) #FOS: Mathematics #Geometric Analysis and Curvature Flows #Homotopy and Cohomology in Algebraic Topology #math.DG #math.DS #msc:37C85 #msc:53A35 #msc:57S20
paper · pdf · doi:10.48550/arxiv.math/0601165
25 pp, to appear in Geometric and Functional Analysis sharpened thm 1.9 to give global description of actions in all cases; added section 8 on structure of orbits of Riemannian type and how Riemannian and Lorentzian orbits meet around degenerate set; many minor corrections and improvements thanks to referee's comments
openalex publication_date 2006/01/09 · arxiv created 2007/04/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The above title is the same, but with "semisimple" instead of "simple," as that of a notice by N. Kowalsky. There, she announced many theorems on the subject of actions of simple Lie groups preserving a Lorentz structure. Unfortunately, she published proofs for essentially only half of the announced results before her premature death. Here, using a different, geometric approach, we generalize her results to the semisimple case, and give proofs of all her announced results.