compositional semantics for complex tenses

We propose a formulation of 'relative tense theory' as applied to the complex tenses in Japanese using an HPSG grammar with its semantics represented based on Discourse Representation Theory. Specifically, a mechanism of tense interpretation which consecutively combines Discourse Representation Structures in parallel with an otherwise motivated hierarchical syntactic structure is presented. The framework provides a concise and comprehensive account of the Japanese simplex and complex tenses; it is made possible by the use of a hypothetical temporal point temporal axis, which relates the location time of the relevant clause to an outer temporal point, and a modal semantic operator woll.