Time Calculus for Natural Language Tagging Guidelines

This paper describes the formalism of a time calculus for natural language, from the perspective of a tagger, whose task is to translate temporal expressions (timex) into the representation described herein. Although in this paper adequate details are given to explain the semantics of various formal constructs, for a more theoretical treatment we refer the readers to [4]. The goals of this representation scheme are: (i) providing an intensional representation for timex; (ii) allowing natural representation and interpretation of under-specification; (iii) facilitating a clean separation from discourse-level force; and (iv) providing a temporal representation that is readily integratable with an event model. A timex can be anything from a prepositional phrase or noun phrase explicitly using time metric units, to other expressions such as adverbial phrases using more vague terms. Several examples are given below: