Dror Bar-Natan (University of Toronto) Wednesday 2 October, 12-1pm, Place: Carslaw 375 Some Feynman Diagrams in Algebra I will explain how the computation of compositions of maps of a certain natural class, from one polynomial ring into another, naturally leads to a certain composition operation of quadratics and to Feynman diagrams. Possibly in a later seminar I will explain how this technology can be used to construct a tangle invariant whose need will be explained in a talk I will be giving in the topology seminar on Sep 16.