Notes
I collect here some expository notes.

Notes from a talk on the HilbertMumford criterion. A proof of the HilbertMumford criterion in the projectiveoveraffine setting is sketched. (pdf)

Linearly reductive algebraic groups in characteristic 0. An expository account of the equivalence between reductivity and linear reductivity in characteristic 0. It also contains a proof of finite generation of the ring of invariants. (pdf)

The absolute Galois group of C(t) (in french). An exposition of a proof that the absolute Galois group of C(t) is isomorphic to the free profinite group on the set of complex numbers. (pdf)