Groups of germs of analytic diffeomorphisms in (C^2,0)
  Let G a group of germs of analytic diffeomorphisms in (C^2,0). We find some remarkable properties supposing that   G is finite, linearizable, abelian nilpotent and solvable. In particular, if the group is abelian and has a generic dicritic diffeomorphisms, then the group is a subgroup of a 1-parametric group. In addition, we study the topological behaviour of the orbits of a dicritic diffeomorphisms. Last, we find some invariants in order to know when two diffeomorphisms are formally conjugates. 
Fabio Enrique Brochero Martinez