ID-rule

An ID-rule X $$\rightarrow$$ $$Y_1,$$ $$Y_2,$$ ..., $$Y_n $$ is interpreted as a well-formedness condition for local trees: It licenses all local trees with a root X and daughters $$Y_1,$$ $$Y_2,$$ ..., $$Y_n $$. The order of the daughters dominated by X is considered to be irrelevant.

Comment
ID-rules were first introduced in Generalized Phrase Structure Grammar. Moder unification-based grammar formalisms like Head-Driven Phrase Structure Grammar use a small number of highly general ID schemata instead.

Formally, the righthand side of an ID-rule can be considered as a multi sets.

Other Languages

 * German ID-Regel