Exercises

1. Find out how NOAH and HACKER implement their constraint posting planning systems.
2. How may the Modal Truth Criterion tell us exactly when a proposition is true? (HINT: See Rich and Knight Ch 13, p 353).
3. Compare constraint posting and state space searching as used in planning systems.
4. You are trying to bolt two metal pates together and they need to positioned precisely relative to one another. If we put a bolt in and tighten it we will be unable to position the parts after doing this. However, if we position the pieces first we wont have a free hand to insert the bolt.

   A solution is clearly to insert the bolt, part tighten it and then position the plates.

   1. Compare this with the Sussman anomaly problem.
   2. Solve this problem using Goal Stack planning.
   3. Solve this problem using Constraint Posting.