This paper describes a compositional semantics for temporal expressions as part of the meaning representation language (MRL) of the JANUS system, a natural language understanding and generation system under joint development by BBN Laboratoires and the Information Sciences Institute. 1 The analysis is based on a higher order intansional logic described in detail in Hinrichs, Ayuso and Scha (1987). Temporal expressions of English are translated into this language as quantifiers over times which bind temporal indices on predicates. The semantic evaluation of time-dependent predicates is defined relative to a set of discourse contexts, which, following Reichenbach (1947), include the.
