Paper: Lazy Unification

ACL ID P90-1023
Title Lazy Unification
Venue Annual Meeting of the Association of Computational Linguistics
Session Main Conference
Year 1990
  • Kurt Godden (General Motors Research Laboratories, Warren MI)

Unification-based NL parsers that copy argument graphs to prevent their destruction suffer from inefficiency. Copying is the most expensive operation in such parsers, and several methods to reduce copying have been devised with varying degrees of success. Lazy Unification is presented here as a new, conceptually elegant solution that reduces copying by nearly an order of magnitude. Lazy Unification requires no new slots in the structure of nodes, and only nominal revisions to the unification algorithm. PROBLEM STATEMENT degradation in performance. This performance drain is illustrated in Figure 1, where average parsing statistics are given for the original implementation of graph unification in the TASLINK natural language system. TASLINK was built upon the LINK parser in a joint project b...