Pseudo-Differential Operators
摘要
How to act on a function to study its regularity? How to act on a partial differential equation to conjugate it to a simpler equation? There are many answers to these questions. Those that we will study in this part come from microlocal analysis. This is a theory that has developed since the sixties, notably under the impulse of Lars Hörmander, Alberto Calderón, Robert Kohn, and Louis Nirenberg.