Categorical actions and multiplicities in the Deligne category Rep_(GLt)

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


We study the categorical type A action on the Deligne category Dt=Rep_(GLt) (t∈C) and its “abelian envelope” Vt constructed in [13]. For t∈Z, this action categorifies an action of the Lie algebra slZ on the tensor product of the Fock space F with Ft , its restricted dual “shifted” by t, as was suggested by I. Losev. In fact, this action makes the category Vt the tensor product (in the sense of Losev and Webster, [20]) of categorical slZ-modules Pol and Polt . The latter categorify F and Ft respectively, the underlying category in both cases being the category of stable polynomial representations (also known as the category of Schur functors), as described in [16,18]. When t∉Z, the Deligne category Dt is abelian semisimple, and the type A action induces a categorical action of slZ×slZ. This action categorifies the slZ×slZ-module F⊠F, making Dt the exterior tensor product of the categorical slZ-modules Pol, Pol. Along the way we establish a new relation between the Kazhdan–Lusztig coefficients and the multiplicities in the standard filtrations of tilting objects in Vt.

Original languageEnglish
Pages (from-to)391-431
Number of pages41
JournalJournal of Algebra
StatePublished - 15 Jun 2018


  • Categorical actions
  • Deligne categories

ASJC Scopus subject areas

  • Algebra and Number Theory


Dive into the research topics of 'Categorical actions and multiplicities in the Deligne category Rep_(GLt)'. Together they form a unique fingerprint.

Cite this