In this analysis, neither of the constituents determine the category, meaning that it is an exocentric construction. Some linguists believe that the label of this structure can be symmetrically determined by the constituents, and others believe that this structure lacks a label altogether. In order to indicate a predicative relationship between the subject (in this case, the NP Mary), and the predicate (AP smart), some have suggested a system of co-indexation, where the subject must c-command any predicate associated with it.