Sandewall, E. (1988). Non-Monotonic Entailment for Reasoning about Time and Action. Part I: Sequential Actions. Technical Report LiTH-IDA-R-88-27, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: The paper defines a logic for reasoning about time and action, in terms of syntax, semantics, and preference relations on interpretations. Temporal logic with explicit representation of time-points is used, rather than situation calculus. The preference relations prefer (1) interpretations which maximize the expectations that fluents do not change, (2) interpretations which minimize the number of instances where fluents change in spite of expectations to the opposite, and (3) interpretations which minimize the set of actions. The preferential entailment relation based on these preferences is equally applicable to temporal projection, temporal explanation, and plan construction (as used for planning, story understanding, and diagnosis). A number of examples are described supporting the thesis that this semantics obtains the results dictated by common sense.
CS Dept TR Overview