Search Space Pruning: A Simple Solution for Better Coreference Resolvers

Abstract

There is a significant gap between the performance of a coreference resolution system on gold mentions and on system mentions. This gap is due to the large and unbalanced search space in coreference resolution when using system mentions. In this paper we show that search space pruning is a simple but effi-cient way of improving coreference resolvers. By incorporating our pruning method in one of the state-of-the-art coreference resolution systems, we achieve the best reported over-all score on the CoNLL 2012 English test set. A version of our pruning method is available with the Cort coreference resolution source code.