On Progression and Query Evaluation in First-Order Knowledge Bases with Function Symbols. Belle, V. & Lakemeyer, G. In Twenty-second International Joint Conference on Artificial Intelligence (IJCAI-11) , Barcelona, Spain, 2011. AAAI Press, AAAI Press.
On Progression and Query Evaluation in First-Order Knowledge Bases with Function Symbols [pdf]Paper  abstract   bibtex   12 downloads  
In a seminal paper, Lin and Reiter introduced the notion of progression of basic action theories. Unfortunately, progression is second-order in general. Recently, Liu and Lakemeyer improve on earlier results and show that for the local-effect and normal actions case, progression is computable but may lead to an exponential blow-up. Nevertheless, they show that for certain kinds of expressive first-order knowledge bases with disjunctive information, called proper$^+$, it is efficient. However, answering queries about the resulting state is still undecidable. In this paper, we continue this line of research and extend proper$^+$ KBs to include functions. We prove that their progression wrt local-effect, normal actions, and range-restricted theories, is first-order definable and efficiently computable. We then provide a new logically sound and complete decision procedure for certain kinds of queries.

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