To validate our method for computing and representing deltas, as well as to have a vehicle for studying the performance of our algorithms, we have implemented a program for computing and representing changes in structured documents. In Section 6.1, we describe the implementation of this program, called LaDiff . In Section 6.2, we study the running time of FastMatch, and in Section 6.3, we discuss the effect of the Assumption 2 of Section 5 on the quality of the solution produced by FastMatch.