Head-driven Phrase Structure Grammar I

Basic Idea Typed feature structure HPSG: First glance
Unification: Informal idea
◮ Unification is a binary operation over two features
structures F and F ′ , used for comparing or combining
information.
◮ Unification of F and F ′ either returns
◮ a merged feature structure with the information from both
F and F ′ ,
◮ or false if F and F ′ are incompatible.
◮ The unification symbol is ⊔.
Example
[
◮ number
[
◮ number
◮ [ number
]
PL ⊔
[
number
] [
PL ⊔ number
] [
]
PL ⊔ person 2 =
] [
PL = number
]
SG = False
[ ]
number PL
person 2
]
PL
Weiwei Sun Head-driven Phrase Structure Grammar I 33/61