Representing calendar expressions with finite-state transducers that bracket periods of time on a hierarchical timeline

This paper proposes representing the se-mantics of natural-language calendar ex-pressions as a sequence of compositions of finite-state transducers (FSTs) that bracket the denoted periods of time on a finite time-line of nested calendar periods. In addition to simple dates and times of the day, the ap-proach covers more complex calendar ex-pressions. The paper illustrates the model by walking through the representation of the calendar expression January to March and May 2007. The representation of the ex-pressions considered is compositional with reference to their subexpressions. The pa-per also outlines possible applications of the model, based on finding the common peri-ods of time denoted by two calendar expres-sions.