Categories of Sheaves in Representation Theory

University Of California-Riverside, Riverside CA

Investigators

Abstract

Representation theory is the study of symmetries in algebra. An understanding of symmetry allows us to reduce complicated problems to simpler ones. Algebra can be used to describe a wide range of phenomena and structures throughout mathematics and the real world, and consequently representation theory has many important applications. Sheaves are geometric objects that generalize the usual notion of functions and have proven to be extremely effective in advancing our understanding of representation theory. This research project aims to uncover finer information about sheaves and applications of this information to representation theory. Parity sheaves were introduced by the PI and his collaborators as a tool for studying the representation theory of reductive groups in positive characteristic. The study of parity sheaves has also suggested the existence of new structures in categories of perverse sheaves. The PI will explore these structures in some special, important, cases and their expected applications in a number of areas including the representations of Hecke algebras and modular representations of finite groups of Lie type. The geometric spaces to be studied are nilpotent cones and their generalizations for symmetric pairs and in gauge theory, as well as (generalized) flag varieties and toric varieties. The proposed methods include utilizing cohomological parity vanishing properties, nearby cycles and hyperbolic localization functors. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.