Grammar Rules in HPSG
HPSG attempts to capture both the regularities and the irregularities of language. Consequently, there are both very general and highly specific grammar rules.
On this page, we will only look at the general rules.
The purpose of the grammar rules is to provide the means for lexical items to satisfy their selectional requirements. The grammar rules correspond to the grammatical functions: complement, specifier, and modifier.
The rules are stated in a way that is compatible with the analysis in Sag/Wasow/Bender 2003, but we mention the full specification of all valence lists.
The Head-Complement Rule
The head is a word and combines with all its complements at once. The mother has an empty COMPS list and its SPR value is identical with that of the head daughter.
The Head-Complement Rule, adapted from Sag/Wasow/Bender 2003
The Head-Specifier Rule
The head has an empty COMPS list and one element on its SPR list. The nonhead is identical to the element on the SPR list of the head. On the mother both valence lists, COMPS and SPR, are empty.
The Head-Specifier Rule, adapted from Sag/Wasow/Bender 2003
The Head-Modifier Rule
The head has an empty COMPS list. The nonhead has one element on its MOD list. The head is identical with the element on the nonhead's MOD list. On the mother, all VAL values are identical to that of the head daughter.
The Head-Modifier Rule, adapted from Sag/Wasow/Bender 2003
- version for pre-modifiers:
- version for post-modifiers: