Before revision:  For example, our experiments on a challenging summarization task of long documents show that our method is much faster and up to 16 times more memory efficient while significantly outperforming both dense and state-of-the-art sparse transformer models.
After revision:  For example, our experiments on a challenging summarization task of long documents show that our method is over 3 times faster and up to 16 times more memory efficient while significantly outperforming both dense and state-of-the-art sparse transformer models.