Minimal Set of Constraints for 2D Constrained Delaunay Reconstruction

Given a triangulation T of n points in the plane, we are interested in the minimal set of edges in T such that T can be reconstructed from this set (and the vertices of T ) using constrained Delaunay triangulation. We show that this minimal set consists of the non locally Delaunay edges, and that its cardinality is less than or equal to n+i=2 (if i is the number of interior points in T ), which is a tight bound