Fei Song, Robin Cohen
This paper describes an algorithm for the interpretation of temporal relations between events mentioned in narrative (such as which event occurs before another). These relations are decided through three different levels of linguistic concepts: aspectual information for verbs, time relations for tenses, and time relations between clauses and/or sentences. One contribution of this paper is to present a more rigorous description for time relations of tenses, which is able to express all the 16 tenses in English and incorporate the interval properties of events from the aspectual analysis into the tense relations. For interpreting time relations between clauses, we emphasize the use of anaphoric references to events and introduce the concept of a situational description for an event (including the participants, place, time duration, etc.), used to make the interpreting algorithm deterministic, i.e. the set of interpreting rules are applied in a fixed order rather than in parallel. Last, we suggest a tree-like structure for the representation of temporal relations between events, which allows us to include vaguely specified relations (which may be clarified later), to facilitate the interpretation of subsequent temporal relations.