Before revision:  We reduced this into an O(n) operation using a two-step approach that involves choosing only a tiny fraction of character-pairs to perform pairwise attention on while still being effective in this task. Our approach performs at least 9-27 \% better than methods based on state-of-the-art paragraph embedding representations.
After revision:  We reduced this into an O(n) operation using a two-step approach that balances performance and efficiency, we managed to achieve 9-27 \% better than methods based on state-of-the-art paragraph embedding representations.