Answer the question about the paper after reading it carefully. To evaluate if the Transformer can generalize to other tasks we performed experiments on English constituency parsing. This task presents specific challenges: the output is subject to strong structural constraints and is significantly longer than the input. Furthermore, RNN sequence-to-sequence models have not been able to attain state-of-the-art results in small-data regimes. Question: What is English constituency parsing?

English constitu ency parsing is a natural language processing task that involves ident ifying the s ynt actic structure of a sentence by breaking it down into smaller units called constitu ents . The output of constitu ency parsing is a tree - like structure that represents the s ynt actic dependencies between the words in the sentence . This task is important for understanding the meaning and grammar of a sentence , and it has applications in tasks such as machine translation and text summar ization . </s>