4 papers
Centers for the restricted category O at the critical level over affine Kac-Moody algebras
Johannes Kübel
The restricted category O at the critical level over an affine Kac-Moody algebra is a certain subcategory of the ordinary BGG-category O. We study a deformed version introduced by…
Jantzen sum formula for restricted Verma modules over affine Kac-Moody algebras at the critical level
Johannes Kübel
For a restricted Verma module of an affine Kac-Moody algebra at the critical level we describe the Jantzen filtration and give an alternating sum formula which corresponds to the J…
Tilting modules in category O and sheaves on moment graphs
Johannes Kübel
We describe tilting modules of the deformed category O over a semisimple Lie algebra as certain sheaves on a moment graph associated to the corresponding block of category O. We pr…
From Jantzen to Andersen Filtration via Tilting Equivalence
Johannes Kübel
The space of homomorphisms from a projective object to a Verma module in category O inherits an induced filtration from the Jantzen filtration on the Verma module. On the other han…