LTIMEX: Representing the local semantics of temporal expressions

Semantic information retrieval requires that we have a means of capturing the semantics of documents; and a potentially useful feature of the semantics of many documents is the temporal information they contain. In particular, the temporal expressions contained in documents provide important information about the time course of the events those documents describe. Unfortunately, temporal expressions are often context-dependent, requiring the application of information about the context in order to work out their true values. We describe a representational formalism for temporal information that captures what we call the local semantics of such expressions; this permits a modularity whereby the context-independent contribution to meaning can be computed independently of the global context of interpretation, which may not be immediately or easily available. Our representation, LTIMEX, is intended as an extension to widely-used TIMEX2 and TimeML representations.