[1P4-GS-6] Language media processing: basic theory

[1P4-GS-6-03] Use of empty categories for conversion of phrase structure into dependency structure

〇Mikiteru Kobayashi¹, Yoshihide Kato¹, Shigeki Kobayashi Matsubara¹ (1. Nagoya University)

[[Online]]

Keywords:syntactic structure, parsing

Syntactic conversion methods are useful for comparing the performance of parsers that are based on different syntactic formalism. Most of the methods, however, do not treat empty categories, which the current phrase structure parsers can identify. This paper proposes a method that uses empty category information for conversion from phrase structures into dependency structures. Our proposed method converts a phrase structure of Penn Treebank (PTB) into a dependency structure of Enhanced Universal Dependencies (EUD). The method copies the phrase structures corresponding to empty categories and replaces each empty category with the corresponding phrase structure. This treatment of empty categories enables us to derive dependency relations that are represented by empty categories.