G-modules, Springer's representations and bivariant Chern classes
G-modules, Springer's representations and bivariant Chern classes
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G 模块、Springer 表示和二变 Chern 类
DOI:
10.1016/0001-8708(86)90064-2
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发表时间:
1986
影响因子:
1.7
通讯作者:
V. Ginsburg
中科院分区:
文献类型:
--
作者:
V. Ginsburg
0.1. Let G be a connected simply connected complex semi-simple Lie group with Lie algebra 6 and Bore1 subgroup B. There are basically two different approaches to the study of simple G-modules. The first one is connected with the Flag manifold X= G/B and G-modules are related to vector bundles and sheaves on X. The second approach, the so-called Kirillov-Kostant“orbit method,” links representations with coadjoint orbits in the dual space 6* of the Lie algebra 8. In 1981 Borho and Brylinski and the author independently developed the idea of joining these two pictures together, thus describing B-modules and primitive ideals by their characteristic varieties in 6* x X. In a recent paper Kashiwara and Tanisaki [KT] related characteristic cycles of holonomic systems on the Flag manifold to Weyl group representations. Here we explain that relation by means of a new “Lagrangian” construction of Springer’s representations. We also show that Springer’s representations are in turn just a special case of the general bivariant theory of Chern classes for singular varieties. With regard to B-modules we will give two proofs of the irreducibility of the associated variety of a primitive ideal in an enveloping algebra of a complex semi-simple Lie algebra. The first of them (see Section 1) appeared in [KT] and is heavily based on results of Joseph. The second (see Section 8), while independent of Joseph’s results,. uses a certain property of Kazhdan-Lusztig cells, verified by Barbasch and Vogan and Lusztig. 1