2024/10/10 by Jakob Hedicke, Hedicke, Jakob, Karl‐Hermann Neeb +1 · 1 citation
Mathematics · #22E15 #53C35 #53C50 #Advanced Mathematical Physics Problems #Differential Geometry (math.DG) #FOS: Mathematics #FOS: Physical sciences #Group Theory (math.GR) #Holomorphic and Operator Theory #Mathematical Physics (math-ph) #Nonlinear Partial Differential Equations
paper · pdf · doi:10.48550/arxiv.2410.08083
openalex publication_date 2024/10/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
An element g of a Lie group is called stably elliptic if it is contained in the interior of the set Ge of elliptic elements, characterized by the property that Ad(g) generates a relatively compact subgroup. Stably elliptic elements appear naturally in the geometry of causal symmetric spaces and in representation theory. We characterize stably elliptic elements in terms of the fixed point algebra of Ad(g) and show that the connected components of the set Gse of stably elliptic elements can be described in terms of the Weyl group action on a compactly embedded Cartan subalgebra. In the case of simple hermitian Lie groups we relate stably elliptic elements to maximal invariant cones and the associated subsemigroups. In particular we show that the basic connected component Gse(0) can be characterized in terms of the compactness of order intervals and that Gse(0) is globally hyperbolic with respect to the induced biinvariant causal structure.