Birational geometry and deformations of nilpotent orbits
Birational geometry and deformations of nilpotent orbits
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DOI：
10.1215/00127094-2008-022
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发表时间：
2006-11
影响因子：
2.5
通讯作者：
Y. Namikawa
中科院分区：
文献类型：
--
作者：
Y. Namikawa
这是数学AG/0408274的继续，在那里我们描述了复单李代数中幂零轨道闭包的Springer分解的相对可动锥。但是，在一般情况下，可动锥不符合整个空间的数值类的因子的斯普林格决议。本文的目的是描述剩余部分。我们将首先根据Brieskorn和Slodowy以规范的方式构造幂零轨道闭包的变形，然后描述它的所有crepant同时解决方案。这种结构使我们能够将整个空间分成有限数量的腔室。此外，通过使用这种构造，可以将数学AG/0408274的主要结果推广到任意Springer映射度> 1的Richardson轨道。在双有理几何中，这类轨道将出现不同于A、D、E_6型的新Mukai翻转。
This is a continuation of math.AG/0408274, where we have described the relative movable cone for a Springer resolution of the closure of a nilpotent orbit in a complex simple Lie algebra. But, in general, the movable cone does not coincide with the whole space of numerical classes of divisors on the Springer resolution. The purpose of this paper is, to describe the remainder. We shall first construct a deformation of the nilpotent orbit closure in a canonical manner according to Brieskorn and Slodowy, and next describe all its crepant simultaneous resolutions. This construction enables us to divide the whole space into a finite number of chambers. Moreover, by using this construction, one can generalize the main result of math.AG/0408274 to arbitrary Richardson orbits whose Springer maps have degree > 1. New Mukai flops, different from those of type A,D,E_6, will appear in the birational geometry for such orbits.