Birational geometry of symplectic resolutions of nilpotent orbits II
Abstract
Description
In this paper we shall study symplectic resolutions of a nilpotent orbit closure of a complex simple Lie algebra \g. We shall introduce an equivalence relation in the set of parabolic subgroups of $G$ in terms of marked Dynkin diagrams. We start with a nilpotent orbit closure which admits a Springer resolution with a parabolic subgroup $P_0$ of $G$. Then we prove that all symplectic resolution of the nilpotent closure are Springer resolutions with $P$ which are equivalent to $P_0$. Here all symplectic resolutions are connected by Mukai flops. We need three types of Mukai flops (types A, D and E_6) in connecting symplectic resolutions. In particular, Mukai flops of type E_6 are new.
All arguments of Part I : math.AG/0404072 which use flags, are replaced by those which use only Dynkin diagrams.
Main results hold for arbitrary simple Lie algebras, that is, the conjectual part in the previous version is established
Main results hold for arbitrary simple Lie algebras, that is, the conjectual part in the previous version is established