Representing Calendar Expressions with Finite-State Transducers that Bracket Periods of Time on a Hierachical Timeline

This paper proposes representing the semantics of natural-language calendar expressions as a sequence of compositions of finite-state transducers (FSTs) that bracket the denoted periods of time on a finite timeline of nested calendar periods. In addition to simple dates and times of the day, the approach covers more complex calendar expressions. The paper illustrates the model by walking through the representation of the calendar expression January to March and May 2007. The representation of the expressions considered is compositional with reference to their subexpressions. The paper also outlines possible applications of the model, based on finding the common periods of time denoted by two calendar expressions.