Logical Status of Heuristics
1. Entailed by operator axioms: conflicts and derived effects
fly(plane,d1,i) and fly(plane,d2,i) conflict
2. Entailed by operators + initial state axioms: state invariants
a truck is at only one location
3. Entailed by operators + initial + goal + length: optimality conditions
do not return a package to a location
4. New constraints on problem instance: simplifying assumptions
Once a truck is loaded, it should immediately move