Paper: A Simple Pattern-Matching Algorithm For Recovering Empty Nodes And Their Antecedents

ACL ID P02-1018
Title A Simple Pattern-Matching Algorithm For Recovering Empty Nodes And Their Antecedents
Venue Annual Meeting of the Association of Computational Linguistics
Session Main Conference
Year 2002
Authors

This paper describes a simple pattern- matching algorithm for recovering empty nodes and identifying their co-indexed an- tecedents in phrase structure trees that do not contain this information. The pat- terns are minimal connected tree frag- ments containing an empty node and all other nodes co-indexed with it. This pa- per also proposes an evaluation proce- dure for empty node recovery procedures which is independent of most of the de- tails of phrase structure, which makes it possible to compare the performance of empty node recovery on parser output with the empty node annotations in a gold- standard corpus. Evaluating the algorithm on the output of Charniak’s parser (Char- niak, 2000) and the Penn treebank (Mar- cus et al. , 1993) shows that the pattern- matching algorithm does sur...