Lie algebra cohomology of infinite-dimensional modules
1980, Advances in Mathematics
https://doi.org/10.1016/0001-8708(80)90041-9Abstract
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This paper discusses the structure of Lie algebra cohomology groups for semisimple Lie algebras, particularly emphasizing infinite-dimensional cases. The author presents a simplified proof of a theorem regarding the relationship between full and relative Lie algebra cohomology groups, utilizing the Hochschild-Serre spectral sequence. The results highlight the finite-dimensional nature of these groups despite their infinite-dimensional settings and their dependence on the topological properties of the maximal compact subgroup.
Key takeaways
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- Theorem 3.13 establishes the structure of Lie algebra cohomology for infinite-dimensional modules.
- Hochschild-Serre spectral sequence relates cohomology groups H*(g,V) and H*(g,k,V) for infinite-dimensional V.
- Cohomology groups of irreducible cyclic modules are finite-dimensional and non-vanishing, contrasting classical results.
- The lowest K type theorem significantly simplifies proofs of core results in the paper.
- The paper outlines applications of spectral sequences in representation theory, particularly for discrete series representations.