Temporal query processing with indefinite information

Time is an important aspect of information in medical domains In this paper we adopt Allen s in uential interval algebra framework for representing temporal information The interval algebra allows the repre sentation of inde nite and incomplete information which is necessary in many applications However answering interesting queries in this frame work has been shown to be almost assuredly intractable We show that when the representation language is su ciently restricted we can develop e cient algorithms for answering interesting classes of queries including i determining whether a formula involving temporal relations between events is possibly true and necessarily true and ii answering aggregation questions where the set of all events that satisfy a formula are retrieved We also show by examining applications of the interval algebra discussed in the literature that our restriction on the representation language often is not overly restrictive in practice