Compactification and trees of spheres covers
  We already saw in [A1] that the space of dynamically marked rational maps can be identified to a subspace of the space of covers between trees of spheres on which there is a notion of convergence that makes it sequentially compact. In the following we describe a topology on this space quotiented by the natural action of its group of isomorphisms. This topology corresponds to the previous convergence notion and makes this space compact. 
Matthieu Arfeux (IMT)
math.DS