# Geometry and Mathematical Physics Seminar 2013/2014

**Thursday 27 February 2014. ** *The Frank Adams Room (Room 1.212), the Alan Turing Building. 3.15pm*
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Pencils of Operators and Their Invariants

Adam Biggs (University of Manchester)

`adam.biggs-2@postgrad.manchester.ac.uk`

We shall discuss the concept of a pencil lifting for the algebra of densities. In particular we will classify the space of liftings that are equivariant with respect to some natural groups: the group of all diffeomorphisms, the group of diffeomorphisms that preserve a volume form, and the projective group. Using these constructions we can find cocycles of the group of diffeomorphisms and we shall go through these constructions.