Extremely lexicalized models for accurate and fast HPSG parsing

Abstract

This paper describes an extremely lexicalized probabilistic model for fast and accurate HPSG parsing. In this model, the probabilities of parse trees are defined with only the probabilities of selecting lexical entries. The proposed model is very simple, and experiments revealed that the implemented parser runs around four times faster than the previous model and that the proposed model has a high accuracy comparable to that of the previous model for probabilistic HPSG, which is defined over phrase structures. We also developed a hybrid of our probabilistic model and the conventional phrasestructure-based model. The hybrid model is not only significantly faster but also significantly more accurate by two points of precision and recall compared to the previous model. © 2006 Association for Computational Linguistics.