Dr. Bas Janssens, University of Utrecht
Central extensions of Lie groups by transgression on mapping spaces
Central extensions of Lie groups play a central role in, for example, the theory of projective representations. Unfortunately, they are not always easy to construct. In this talk, we will be interested in certain infinite dimensional Lie groups of diffeomorphisms, preserving a closed form on a compact, smooth manifold. Using transgression of differential characters on mapping spaces, we construct central extensions of these groups.