**Kenji Fukaya**

Kyoto University, Japan

December 18, 2014

**Why the foundation of differential topology is deeply related to the foundation of quatum field theo**:
How we perturb the diagonal $M subset M imes M$ is known to be related to the foundation of differential topology. The same point is related to the problem of inifinity in quantum field theory.
I want to explain how they are related to each other and also to
foundation of the theory of pseudo-holomorphic curve topological field theory or renomalization.