"The aim of this 5,5 years project is to create around the PI a research group on the control of systems modeled by partial differential equations at the Laboratory Jacques-Louis Lions of the UPMC and to develop with this group an intensive research activity focused on nonlinear phenomena.With the ERC grant, the PI plans to hire post-doc fellows and PhD students, to offer 1-to-3 months positions to confirmed researchers, a regular seminar and workshops.A lot is known on finite dimensional control systems and linear control systems modeled by partial differential equations. Much less is known for nonlinear control systems modeled by partial differential equations. In particular, in many important cases, one does not know how to use the classical iterated Lie brackets which are so useful to deal with nonlinear control systems in finite dimension.In this project, the PI plans to develop, with the research group, methods to deal with the problems of controllability and of stabilization for nonlinear systems modeled by partial differential equations, in the case where the nonlinearity plays a crucial role. This is for example the case where the linearized control system around the equilibrium of interest is not controllable or not stabilizable. This is also the case when the nonlinearity is too big at infinity and one looks for global results. This is also the case if the nonlinearity contains too many derivatives. The PI has already introduced some methods to deal with these cases, but a lot remains to be done. Indeed, many natural important and challenging problems are still open. Precise examples, often coming from physics, are given in this proposal."