Splitting the Reference Time: Temporal Anaphora and Quantification in DRT

Splitting the Reference Time: Temporal Anaphora and Quantification in DRT Rani Nelken Tel-Aviv University Tel-Aviv 69978, Israel nelken@math, tau. ac. il Nissim Francez Computer Science Department The Technion Haifa 32000, Israel francez~cs, technion, ac. il Abstract This paper presents an analysis of tem- poral anaphora in sentences which con- tain quantification over events, within the framework of Discourse Representa- tion Theory. The analysis in (Partee, 1984) of quantified sentences, introduced by a temporal connective, gives the wrong truth-conditions when the tempo- ral connective in the subordinate clause is before or after. This problem has been previously analyzed in (de Swart, 1991) as an instance of the proportion problem, and given a solution from a Generalized Quantifier approach. By using a care- ful distinction between the different no- tions of reference time, based on (Kamp and Reyle, 1993), we propose a solu- tion to this problem, within the frame- work of Dt~T. We show some applica- tions of this solution to additional tem- poral anaphora phenomena in quantified sentences. 1 Introduction The analysis of temporal expressions in natural language discourse provides a challenge for con- temporary semantic theories. (Partee, 1973) in- troduced the notion of temporal anaphora, to ac- count for ways in which temporal expressions de- pend on surrounding elements in the discourse for their semantic contribution to the discourse. In this paper, we discuss the interaction of tempo- ral anaphora and quantification over eventualities. Such interaction, while interesting in its own right, is also a good test-bed for theories of the semantic interpretation of temporal expressions. We dis- cuss cases such as: (1) Before John makes a phone call, he always lights up a cigarette. (Partee, 1984) (2) Often, when Anne came home late, Paul had already prepared dinner. (de Swart, 1991) (3) When he came home, he always switched on the tv. He took a beer and sat down in his armchair to forget the day. (de Swart, 1991) (4) When John is at the beach, he always squints when the sun is shining. (de Swart, 1991) The analysis of sentences such as (1) in (Partee, 1984), within the framework of Discourse Repre- sentation Theory (DRT) (Kamp, 1981) gives the wrong truth-conditions, when the temporal con- nective in the sentence is before or after. In DRT, such sentences trigger box-splitting with the even- tuality of the subordinate clause and an updated reference time in the antecedent box, and the eventuality of the main clause in the consequent box, causing undesirable universal quantification over the reference time. This problem is analyzed in (de Swart, 1991) as an instance of the proportion problem and given a solution from a Generalized Quantifier approach. We were led to seek a solution for this problem within DRT, because of DRT's advantages as a general theory of discourse, and its choice as the underlying formalism in another research project of ours, which deals with sentences such as 1-4, in the context of natural language specifications of computerized systems. In this paper, we pro- pose …

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