arXiv subjects

Konstantin Styrkas

Publications and source records attributed to Konstantin Styrkas.

3 recordsLinked to original sources

arXiv2004

Regular representation on the big cell and big projective modules in the category O

We study the algebra of regular functions on the big cell of the Gauss decomposition of a simple complex Lie group G. We prove that it is spanned by the matrix elements of big projective modules in the BGG category O, and admits a decomposition of Peter-Weyl type. The subspace of Whittaker vectors in the regular representation on the big cell gives a realization of the big projective modules in O, similar to the Borel-Weil theorem. These results can be extended to the quantum groups.

math.RT↗

arXiv2004

Modified regular representations of affine and Virasoro algebras, VOA structure and semi-infinite cohomology

We identify the algebra of matrix elements of big projective modules in category O with the regular functions on the big Bruhat cell of G. Analogous extensions of the regular representations of the affine Lie and Virasoro algebras yield vertex operator algebras, equipped with two commuting actions with special values of the total central charge. In the generic case, we identify the structure of these VOAs, compute their semi-infinite cohomology. Its superalgebra structure encodes the fusion rules for the associated tensor categories. Full details are provided for the affine sl(2) and Virasoro algebras, and various generalizations and extensions are discussed.

math.QA↗

arXiv1996

Algebraic integrability of Macdonald operators and representations of quantum groups

In this paper we construct examples of commutative rings of difference operators with matrix coefficients from representation theory of quantum groups, generalizing the results of our previous paper to the $q$-deformed case. A generalized Baker-Akhiezer function $Ψ$ is realized as a matrix character of a Verma module and is a common eigenfunction for a commutative ring of difference operators. In particular, we obtain the following result in Macdonald theory: at integer values of the Macdonald parameter $k$, there exist difference operators commuting with Macdonald operators which are not polynomials of Macdonald operators. This result generalizes an analogous result of Chalyh and Veselov for the case $q=1$, to arbitrary $q$. As a by-product, we prove a generalized Weyl character formula for Macdonald polynomials (a conjecture by G.Felder and A.Varchenko), the duality for the $Ψ$-function, and the existence of shift operators.

q-alg↗