Transformation Groups

, Volume 15, Issue 3, pp 517–549

A categorical approach to Weyl modules


    • Department of MathematicsUniversity of California
  • Ghislain Fourier
    • Mathematisches InstitutUniversität zu Köln
  • Tanusree Khandai
    • Harish-Chandra Research Institute

DOI: 10.1007/s00031-010-9090-9

Cite this article as:
Chari, V., Fourier, G. & Khandai, T. Transformation Groups (2010) 15: 517. doi:10.1007/s00031-010-9090-9


Global and local Weyl modules were introduced via generators and relations in the context of affine Lie algebras in [CP2] and were motivated by representations of quantum affine algebras. In [FL] a more general case was considered by replacing the polynomial ring with the coordinate ring of an algebraic variety and partial results analogous to those in [CP2] were obtained. In this paper we show that there is a natural definition of the local and global Weyl modules via homological properties. This characterization allows us to define the Weyl functor from the category of left modules of a commutative algebra to the category of modules for a simple Lie algebra. As an application we are able to understand the relationships of these functors to tensor products, generalizing results in [CP2] and [FL]. We also analyze the fundamental Weyl modules and show that, unlike the case of the affine Lie algebras, the Weyl functors need not be left exact.

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© Springer Science+Business Media, LLC 2010