BASE

Categorial component

Lexical items are then inserted by substitution transformations which take account of the feature specification of each item. Thus, in the example above the terminal string might be The mountain frightens the boy or The boy chases the rabbit but not *The rabbit praises the boy or *The boy chases the mountain. Because of the recursive power provided by rules such as 2 of the categorial component it is possible to generate infinitely many base or deep structures.