Chinese Zero Pronoun Resolution: A Chain to Chain Approach

摘要

Chinese zero pronoun (ZP) resolution plays a critical role in discourse analysis. Different from traditional mention to mention approaches, this paper proposes a chain to chain approach to improve the performance of ZP resolution from three aspects. Firstly, consecutive ZPs are clustered into coreferential chains, each working as one independent anaphor as a whole. In this way, those ZPs far away from their overt antecedents can be bridged via other consecutive ZPs in the same coreferential chains and thus better resolved. Secondly, common noun phrases (NPs) are automatically grouped into coreferential chains using traditional approaches, each working as one independent antecedent candidate as a whole. Then, ZP resolution is made between ZP coreferential chains and common NP coreferential chains. In this way, the performance can be much improved due to the effective reduction of search space by pruning singletons and negative instances. Finally, additional features from ZP and common NP coreferential chains are employed to better represent anaphors and their antecedent candidates, respectively. Comprehensive experiments on the OntoNotes corpus show that our chain to chain approach significantly outperforms the state-of-the-art mention to mention approaches. To our knowledge, this is the first work to resolve zero pronouns in a chain to chain way.