Commutative avatars of representations of semisimple Lie groups
arXiv:2311.02711 · doi:10.1073/pnas.2319341121
Abstract
Here we announce the construction and properties of a big commutative subalgebra of the Kirillov algebra, called big algebra, attached to a finite dimensional irreducible representation of a complex semisimple Lie group. They are commutative finite flat algebras over the cohomology of the classifying space of the group. They are isomorphic with the equivariant intersection cohomology of affine Schubert varieties, endowing them with a new ring structure. Study of the finer aspects of the structure of the big algebras will also furnish the stalks of the intersection cohomology with ring structure, thus ringifying Lusztig's q-weight multiplicity polynomials i.e. affine Kazhdan-Lusztig polynomials.
original title "Big algebras" changed to match published version; 4.2 is replaced for visualisations and clarifications; 15 pages, 9 figures