Summary
Orbit decompositions play a fundamental role in the study of symmetric k-varieties and their applications to representation theory and many other areas of mathematics, such as geometry, the study of automorphic forms and character sheaves. Symmetric k-varieties generalize symmetric varieties and are defined as the homogeneous spaces G k /H k , where G is a connected reductive algebraic group defined over a field k of characteristic not 2, H the fixed point group of an involution σ and G k (resp., H k ) the set of k-rational points of G (resp., H).
In this contribution we give a survey of results on the various orbit decompositions which are of importance in the study of these symmetric k-varieties and their applications with an emphasis on orbits of parabolic k-subgroups acting on symmetric k-varieties. We will also discuss a number of open problems.
Mathematics Subject Classification (2000): 20G20, 22E15, 22E46, 53C35
Dedicated to Gerry Schwarz on the occasion of his 60th birthday
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Helminck, A.G. (2010). On Orbit Decompositions for Symmetric k-Varieties. In: Campbell, H., Helminck, A., Kraft, H., Wehlau, D. (eds) Symmetry and Spaces. Progress in Mathematics, vol 278. Birkhäuser Boston. https://doi.org/10.1007/978-0-8176-4875-6_6
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