On Numbers of Pseudo-Triangulations
  We study the maximum numbers of pseudo-triangulations and pointed pseudo-triangulations that can be embedded over a specific set of points in the plane or contained in a specific triangulation.   We derive the bounds $O(5.45^N)$ and $\Omega (2.41^N)$ for the maximum number of pointed pseudo-triangulations that can be contained in a specific triangulation over a set of $N$ points. For the number of all pseudo-triangulations contained in a triangulation we derive the bounds $O^*(6.54^N)$ and $\Omega (3.30^N)$. We also prove that $O^*(89.1^N)$ pointed pseudo-triangulations can be embedded over any specific set of $N$ points in the plane, and at most $120^N$ general pseudo-triangulations. 
Moria Ben-Ner, Andr\'e Schulz, Adam Sheffer
cs.CG cs.DM math.CO