The topological Duflo isomorphism 

The Duflo isomorphism in Lie theory is an isomorphism between the invariant
part of the symmetric algebra of a given Lie algebra, and the centre of its
universal enveloping algebra. In 2003, Bar-Natan, Le and Thurston gave
a topological proof for metrised Lie algebras. In this talk we give
a topological proof in the general case, using a universal finite type
invariant for certain knotted tubes in R^4, constructed recently by
Bar-Natan and the speaker. (Joint work with Dror Bar-Natan.)