so that there are KO0 screws initially, engine El requires 40 screws, and engine E:2 requires 50 screws. 'The + and

- function symbols may be used in effect literals for resources.

b. Explain how the definition of conflict between causal links and actions in partial-order planning must be modified to handle consumabl~: resources.

c. Some actions-for example, resupplying the factory with screws or refueling a carcan irzcrease the availability of resources. A reslource is monotonically non-increasing if no action increases it. Explain how to use this property to prune the search space.