The type sign has two subtypes, word and phrase. The type of the feature HEAD encodes the syntactic category of the sign. For type verb, the feature VFORM (which can have values such inf, fin or prt) is appropriate. For type noun, the feature CASE (with values such as nom or acc) is appropriate. The feature SUBCAT encodes the syntactic valence information of the sign. Following recent work in HPSG we assume that the feature ARG-S encodes the argument structure. This is the level at which e.g. binding theory applies, and where control relations are established. This feature will be motivated in section 5. The feature DIR encodes the direction in which a head selects its argument (cf. section 3.3). The features SLASH/SMALL>_INHER, SLASH/SMALL>_TOBIND are used in the analysis of non-local dependencies. The type sign itself has two subtypes, word and phrase. In section 6 we introduce the features VR (which is appropriate for verbs) and PFX (which is appropriate for signs).
We use the following abbreviations. NP will be used for a nominal sign with an empty subcat list. S stands for a finite verbal sign with an empty SUBCAT list. VP will be used for a verbal sign with an empty subcat list. V will be used for lexical verbal signs. Finally PVP (partial VP) will be used for anything that is verbal.