University of Sydney Algebra Seminar

Vinoth Nandakumar (Massachusetts Institute of Technology)

Friday 20th July, 12:05-12:55pm, Carslaw 175

Exotic t-structures for two-block Springer fibres

We study the exotic t-structure on the derived category of coherent sheaves on the Springer fibre for a two-block nilpotent. The exotic t-structure has been defined by Bezrukavnikov and Mirkovic for any exact base change of the Springer resolution. Using work of Cautis and Kamnitzer, we construct functors indexed by affine tangles, between categories of coherent sheaves on different two-block Springer fibres. After checking some exactness properties of these functors, we describe the irreducible objects in the heart of the exotic t-structure for the nilpotent of type \((m+n,n)\) and enumerate them by crossingless \((m,m+2n)\) matchings.