Abstract
These papers arose from my collaboration with Raoul during my stay at Harvard. I was there as a postdoc in physics, in the group of Arthur Jaffe. It was the critical time when I had to decide what to do with my life, including whether I should complete my move to mathematics. At the time I was working on perturbative topological field theories and one day, while I was alone in my office, I was visited by a tall guy who said he was interested in what I was doing and wished to start a collaboration to apply my results.
Cattaneo, Alberto Sergio