A Process Algebraic Approach to Computational Linguistics

The thesis presents a way to apply process algebra to computational linguistics.1 We are interested in how contexts can a ect or contribute to language understanding and model the phenomena as a system of communicating processes to study the interaction between them in detail. For this purpose, we turn to the -calculus and investigate how communicating processes may be de ned. While investigating the computational ground of communication and concurrency, we devise a graphical representation for processes to capture the structure of interaction between them. Then, we develop a logic, combinatory intuitionistic linear logic with equality relation, to specify communicating processes logically. The development enables us to study Situation Semantics with process algebra. We construct semantic objects employed in Situation Semantics in the -calculus and then represent them in the logic. Through the construction, we also relate Situation Semantics with the research on the information ow, Channel Theory, by conceiving of linear logic as a theory of the information ow. To show how sentences can be parsed as the result of interactions between processes, we present a concurrent chart parser encoded in the -calculus. We also explain how a semantic representation can be generated as a process by the parser. We conclude the thesis by comparing the framework with other approaches. The ideas presented in the dissertation have been presented at three occasions. The idea to apply process algebra to studying Situation Theory was rst presented at the rst International Workshop on Computational Semantics held at the Institute for Language Technology and Arti cial Intelligence, Tilburg University, The Netherlands in December 1994 [Fuj94]. The idea was re ned and presented also at the 10th Amsterdam Colloquium held at ILLC/Department of Philosophy, University of Amsterdam, The Netherlands in December 1995 [Fuj96b]. Another idea to apply process algebra to studying feature structures and parsing was presented at the second Conference on Information-Theoretic Approaches to Logic, Language, and Computation held at London Guildhall University in July 1996 [Fuj96a].