  Implicit discourse relation classification is one of the most difficult parts
in shallow discourse parsing as the relation prediction without explicit
connectives requires the language understanding at both the text span level and
the sentence level. Previous studies mainly focus on the interactions between
two arguments. We argue that a powerful contextualized representation module, a
bilateral multi-perspective matching module, and a global information fusion
module are all important to implicit discourse analysis. We propose a novel
model to combine these modules together. Extensive experiments show that our
proposed model outperforms BERT and other state-of-the-art systems on the PDTB
dataset by around 8% and CoNLL 2016 datasets around 16%. We also analyze the
effectiveness of different modules in the implicit discourse relation
classification task and demonstrate how different levels of representation
learning can affect the results.
