Modular HPSG [Head-driven Phrase Structure Grammar]

We present a detailed description of the modular Head-driven Phrase Structure Grammar (HPSG). Although the notion of modularity is known in the area of programming languages, and it is described for context-free grammars (CFG), this is the first attempt at defining modularity for HPSGs. We describe and formally define modularity for an HPSG-type grammar, and we illustrate its application on an example.