The Goldman and Fock-Goncharov coordinates for convex projective   structures on surfaces
  Let P(S) be the space of convex projective structures on a surface S with negative Euler characteristic. Goldman and Bonahon-Dreyer constructed two different sets of global coordinates for P(S), both associated to a pair of pants decomposition of the surface S. The article explicitly describes the coordinate change between these two parametrizations. Most of the arguments are concentrated in the case where S is a pair of pants, in which case the Bonahon-Dreyer coordinates are actually due to Fock-Goncharov. 
Francis Bonahon (University of Southern California) and Inkang Kim   (Korean Institute for Advanced Study)
math.GT