Lecture notes from the cours given at VIASM school on Number Theory (18-24/06/2018, Hanoi, Vietnam). In: "Arithmetic and geometry over local fields", Lecture Notes in Mathematics 2275, 2021, Spriger.

#### Abstract:

The lecture notes below correspond to the course given by the author in occasion of the VIASM school on Number Theory (18-24 June 2018, Hanoi). We have chosen to omit the proofs that are already presented in details in many references in the literature, although they were explained during the lectures, and we have devoted more space to statements useful in the applications.

ArXiv: 2011.00932

HAL: hal-02986455