A remark on Schubert cells and duality of orbits on flag manifolds
  It is known that the closure of an arbitrary K_c-orbit on a flag manifold is expressed as a product of a closed K_c-orbit and a Schubert cell ([M2], [Sp]). We already applied this fact to the duality of orbits on flag manifolds ([GM]). We refine here this result and and give its new applications to the study of domains arising from the duality. 
Simon Gindikin and Toshihiko Matsuki