Trimester Seminar

Venue: HIM, Poppelsdorfer Allee 45, Lecture Hall

Tuesday, October, 24th, 10:00

Noncommutative crepant resolutions of quotient singularities for reductive groups 

Michel Van den Bergh (Universiteit Hasselt)



Wednesday, October, 25th, 10:00 

Arc algebras

Michael Ehrig (University of Sydney)


Originally defined by Khovanov to categorify invariants of tangles, arc algebras have been generalized and modified in different ways. The talk will start with a basic introduction into what arc algebras are, followed by an overview on how they are related to different topics. This will range from Springer fibres and perverse sheaves on Grassmannians on the geometry side, to webs and foams on the side of link and tangle invariant, to the representation theory of Lie algebras and superalgebras, and to the categorification of quantum group representations. 

Thursday, October, 26th, 10:00

Convolution algebras arising from Springer fibers

Arik Wilbert (University of Bonn)


We will explain how to use the irreducible components of Springer fibers to construct interesting convolution algebras. More precisely, the goal is to understand a geometric construction of the arc algebra* obtained by Stroppel-Webster. Along the way we will highlight some intriguing connections between the geometry of Springer fibers, cup diagram combinatorics, 2d TQFTs and Fukaya categories.

*Depending on prior knowledge it might be helpful to attend Michael’s talk to fully appreciate the contents of this talk.