TANIGUCHI Kenji
Department Aoyama Gakuin University Department of Mathematical Sciences, College of Science and Engineering Position Professor |
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Language | English |
Publication Date | 2014/03 |
Type | Academic Journal |
Peer Review | Peer reviewed |
Title | Closed orbits on partial flag varieties and double flag variety of finite type |
Contribution Type | Collaboration |
Volume, Issue, Page | pp.113-119 |
Author and coauthor | Kensuke Kondo, Kyo Nishiyama, Hiroyuki Ochiai |
Details | Let G be a connected reductive algebraic group over C. We denote by K=(Gθ)0 the identity component of the fixed points of an involutive automorphism θ of G. The pair (G,K) is called a symmetric pair. Let Q be a parabolic subgroup of K. We want to find a pair of parabolic subgroups P1, P2 of G such that (i) P1 ∩ P2 = Q and (ii) P1 P2 is dense in G. The main result of this article states that, for a simple group G, we can find such a pair if and only if (G,K) is a Hermitian symmetric pair. The conditions (i) and (ii) imply that the K-orbit through the origin (eP1,eP2) of G/P1 × G/P2 is closed and it generates an open dense G-orbit on the product of partial flag variety. From this point of view, we also give a complete classification of closed orbits on G/P1 × G/P2. |