Compiling Causality into Action Theories

This paper is concerned with the problem of representing the eeects of actions. We argue that the traditional minimal change principle is problematic to represent ramiications of actions that are related to the causality of the domain. To handle this problem properly, it is necessary to describe the causal relations of the domain explicitly and compile the domain causality into action theories. We rst deene causal theories as normal default theories where causal relations are viewed as defeasible default rules, and use Lukaszewicz's model default theory to provide formal semantics for causal theories. We then propose a causality-based minimal change principle for representing the eeects of actions, and show how this principle can be formalized by using causal theories. We also compare our approach with other related work in detail.