Name: Ragnar-Olaf Buchweitz (Toronto)

title: Hochschild Cohomology and the Centre of the Derived
Category
        --- The Case of Kleinian Singularities ---

Abstract:

In every $K$-algebra $A$, the Hochschild cohomology
$HH(A)$ maps naturally to the centre of  $D(A)$.
Here we investigate the stable version of this map
when  $A$  is the graded ring of a Kleinian singularity.
This case is accessible due to the structure theory
of reflexive modules over such rings as embodied in the
McKay correspondence, and because the associated
stable Auslander algebra admits a simple geometric
interpretation through linkage of skew lines in $P^3$.