Canonical Representation In NLP System Design: A Critical Evaluation

This paper is a critical evaluation of an approach to control in natural language processing systems which makes use of canonical structures as a way of collapsing multiple analyses in individual components. We give an overview here of how the Lucy natural language interface system currently realizes this control model and then evaluate what we take to be the strengths and weaknesses of such an approach. In particular, we conclude that the use of canonical structures can restrain combinatorial explosion in the search, but at the cost of breaking down the barriers between modules and of letting processing concerns infect the declarative representation of information.