  We describe some theoretical results on triangulations of surfaces and we
develop a theory on roots, decompositions and genus-surfaces. We apply this
theory to describe an algorithm to list all triangulations of closed surfaces
with at most a fixed number of vertices. We specialize the theory for the case
where the number of vertices is at most 11 and we get theoretical restrictions
on genus-surfaces allowing us to get the list of triangulations of closed
surfaces with at most 11 vertices.
