The interface between phrasal and functional constraints

Many modern grammatical formalisms divide the task of linguistic specification into a context free component of phrasal constraints and a separate component of attribute-value or functional constraints. Conventional methods for recognizing the strings of a language also divide into two parts so that they can exploit the different computational properties of these components. This paper focuses on the interface between these components as a source of computational complexity distinct from the complexity internal to each. We first analyze the common hybrid strategy in which a polynomial context-free parser is modified to interleave functional constraint solving with context-free constituent analysis. This strategy depends on the property of monotonicity in order to prune unnecessary computation.