**Wintersemester 2018/19**

**Unless otherwise specified talks take place in room 119 (Arnimallee 3) at 16:15**

**Schedule**

**27th August 2018 Makiko Mase (Tokyo)**

**On dualities among families of K3 surfaces associated to strange duality of singularties**

**18th October 2018****Sebastian Posur (Siegen) **

**Categorical abstraction as a tool for computing with equivariant vector bundles**

Motivated by the difficult task of finding low rank indecomposable vector bundles on projective space, we discuss a construction strategy that exploits categorical abstraction as a powerful computational tool. We will make use of skeletal versions of the tensor category of representations of finite groups over a splitting field, categorically internalized versions of the exterior algebra, and an equivariant version of the BGG correspondence, which is an exact equivalence between the bounded derived category of coherent sheaves on projective space and the stabilization of the category of finitely presented modules over the graded exterior algebra. These computational methods are all provided by our computer algebra project CAP (Categories, Algorithms, Programming).

**25th October 2018****Nathan Ilten-Gee (Vancouver) **

**Deformations of smooth complete toric varieties: obstructions and the cup product**

**Abstract:** Let X be a smooth complete toric variety. I will explicitly describe the obstruction space and the cup product map in combinatorial terms. Using this, I give an example of a smooth projective toric threefolds for which the cup product map does not vanish, showing that in general, smooth complete toric varieties may have obstructed deformations. This is joint work with Charles Turo.

**1st November 2018****Dominic Bunnett (FU Berlin) **

**8th November 2018****NO TALK due to NoGags Leipzig!**

**15th November 2018****Matej Filip (Mainz) **

**and**

**Jan Christophersen (Oslo)**

**22nd November **

**?**

**29th November 2018****Achim Hennings **

**6th December 2018 **

**Irem Portakal (Magdeburg)**

**13th December 2018****Frederik Witt (Stuttgart)**

**20th December 2018****No talk due to Magdeburg-Kolloquium**