Unification and some new grammatical formalisms
Aravind K. Joshi · 1987
The key idea in the unification-based approaches to grammar is that we deal with informational structures (called feature structures) which encode a variety of linguistic information (lexical, syntactic, semantic, discourse, perhaps even cross-linguistic) in a uniform way and then manipulate (combine) these structures by means of a few (one, if possible) welldefined operations (unification being the primary one).The feature structures consist of features and associated values, which can be atomic or complex i.e., feature structures themselves.In other'words, the values can be from a structured set.The unification operation builds new structures and together with some string combining operation (concatenation being the primary one) pairs the feature structures with strings (Schieber, 1986).How does the unification formalism differ from the standard context-free grammar formalism?