Natural Language Understanding Wiki

Excerpt from David Vandas et al. (2007)

David Vandas et al. (2007)[1]: "Without the correct bracketing in the Treebank, strictly right-branching trees were created for all base-NPs. This has an unwelcome effect when con- junctions occur within an NP (Figure 1). An additional grammar rule is needed just to get a parse, but it is still not correct (Hockenmaier, 2003, p. 64). The awkward conversion results in bracketing (a) which should be (b):

(a) (consumer ((electronics) and (appliances (retailing chain))))

(b) ((((consumer electronics) and appliances) retailing) chain)"


  1. Vadas, D., & Curran, J. R. (2007). Adding noun phrase structure to the Penn Treebank. 45th Annual Meeting of the Association of Computational Linguistics, (June), 240–247. Retrieved from