Markus
        Linckelmann, City, University of London
    
    
    Title: On
        degree -1 operators in cohomology
    
    
    
      Abstract:
          We describe an elementary construction principle for operators
          of degree -1 on Ext-spaces of modules. We apply this to finite
          group cohomology, and describe in particular the BV operator
          on the Hochschild cohomology of a finite group algebra in
          terms of this construction principle. We use this to calculate
          the Lie algebra structure of the first Hochschild cohomology
          of certain finite p-group algebras. This is joint work with
          Radha Kessar and Dave Benson.