A Comparative Analysis of Centering-Based Algorithms for Pronoun Resolution in Portuguese

Pronominal anaphora resolution consists in finding a referent for a given pronoun. Although being essential for many natural language processing systems, such as automatic translators, text generators and summarizers, there is a myriad of issues regarding this task, particularly when there is more than one possible referent for a given pronoun. Over the years, several approaches have been proposed to deal with this challenge, usually taking only syntactic information into account. On the other hand, methods based on Centering Theory rely on concepts such as coherence, for instance, to do the job. In this work, we describe our implementation and evaluation of existing centering-based algorithms for pronominal resolution in Portuguese. As a result, we indicate both the strong and weak points of each of the tested algorithms, thereby helping other researchers to make a more informed decision about which method to use.