A Causal Completion System (CCS)

By Fangzhen Lin

CCS is a system for specifying the effects of actions. Unlike those commonly used in AI planning, our system uses an action description language that allows one to specify the effects of actions using domain rules, which are state constraints that can entail new action effects from old ones. Declaratively, an action domain in our language corresponds to a nonmonotonic causal theory in the situation calculus. Procedurally, such an action domain is compiled into a set of logical theories, one for each action in the domain, from which fully instantiated successor state-like axioms and STRIPS-like systems are then generated. We expect the system to be a useful tool for knowledge engineers writing action specifications for classical AI planning systems, GOLOG systems, and other systems where formal specifications of actions are needed.

CCS is implemented in SWI-Prolog 3.2.9 (it does not work on versions later than that). This was the last pre-ISO release of SWI-Prolog, and can be downloaded here To run CCS, you need to install SWI-Prolog 3.2.9 interpreter on your machine and download this Prolog source file. Here are some other files/documents that we may want to take a look at:

• Fangzhen Lin. Compiling Causal Theories to Successor State Axioms and STRIPS-Like Systems Journal of AI Research 19 (2003) 279-314. This is the paper that describes the system in details.
• Instruction on how to run the system.
• README file that describes the content of the online appendix of the above JAIR paper. In particular, it contains an annotated version of the blocks world specification using causal rules. So you may also want to take a look at the STRIPS-like output returned by CCS on this domain description.
• Finally, here is the online appendix of the above JAIR paper.