H. Nicolai, «Gauging extended supergravities in three dimensions»

Maximal and non-maximal supergravities in three spacetime dimensions allow for a much richer variety of semisimple, non-semisimple and even complex gaugings than supergravities in four and more spacetime dimensions. In particular, most of these models do not appear to possess a geometrical origin from higher dimensions. In this talk I will review the construction of these theories, concentrating on the most interesting case of maximal (N=16) supergravity, and emphasizing the key role of the so-called embedding tensor in the construction. I will then discuss some of their properties, including the equivalence of Yang-Mills gaugings with certain Chern-Simons gaugings. Finally, as one special application, I will briefly explain how to derive the currently popular rigidly superconformal D=3 models (with N\leq 8) as flat space limits of certain gauged supergravities