Identifier

etd-04152010-174523

Degree

Doctor of Philosophy (PhD)

Department

Mathematics

Document Type

Dissertation

Abstract

For a reductive complex algebraic group, the associated nilpotent cone is the variety of nilpotent elements in the corresponding Lie algebra. Understanding the nilpotent cone is of central importance in representation theory. For example, the nilpotent cone plays a prominent role in classifying the representations of finite groups of Lie type. More recently, the nilpotent cone has been shown to have a close connection with the affine flag variety and this has been exploited in the Geometric Langlands Program. We make use of the following important fact. The nilpotent cone is invariant under the coadjoint action of G on the dual Lie algebra and admits a canonical Poisson structure which is compatible in a strong way with the action of G. We exploit this connection to develop a theory of perverse sheaves on the nilpotent cone that is suitable for the G-equivariant Poisson setting. Building on the work of Beilinson--Bernstein--Deligne and Deligne--Bezrukavnikov, we define a new category, the equivariant Poisson derived category and endow it with a new semiorthogonal filtration, the perverse Poisson t-structure. In order to construct the perverse Poisson t-structure, we also prove an axiomatized gluing theorem for semiorthogonal filtrations in the general setting of triangulated categories which generalizes the construction of the perverse coherent sheaves of Deligne--Bezrukavnikov.

Date

2010

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Achar, Pramod N.

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