DOMAIN-INDEPENDENT TEMPORAL REASONING WITH RECURRING EVENTS

Numerous examples of temporal reasoning involve a process of abstracti on from the number of times an event is to occur or the number of time s events stand in a temporal relation. For example, scheduling a recur ring event such as one's office hours may consider things like the rel ative temporal ordering of the office hours and a number of other even ts in a given work day. The number of times office hours will actually be held may be unknown, even irrelevant, at the time of scheduling th em. The objective of this article is to formulate a domain-independent framework for reasoning about recurring events and their relations. T o achieve this end, we propose an ontology of recurrence based on the model-theoretic structure underlying collective predication using plur al noun phrases. We offer a calculus of binary temporal relations for temporal collections based on a well-defined transformation of interva l temporal relations into recurrence relations. Finally, we describe a reasoning framework based on manipulating knowledge stored in tempora l relation networks, which is in turn a specialization of the CSP (con straint satisfaction problem) framework. The reasoner manipulates recu rrence relations in the network to determine the network's consistency or to generate scenarios.