Persson, T. and Staflin, L. (1990). Cause as an Operator in a Logic with Real-valued Fluents and Continuous Time. Technical Report LiTH-IDA-R-90-45, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: We propose a new method for characterizing the discontinuities in processes that are mostly continuous. We introduce a causal operator that is used to specify when the value of a fluent has a cause. A discontinuity in a fluent is allowed if the fluent's value immediately after the discontinuity has a cause. The causal operator is incorporated in a temporal logic with continuous time and real-valued fluents. The resulting logic is a nonmonotonic logic suitable for representing physical models of real world situations. We define a selection function which given a set of models returns a subset of the models. This selection function defines a nonmonotonic entailment operator. The intuitive idea behind the selection function is that is should select all models where all discontinuities are ``specified'' as allowed.
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