The following examples illustrate the use of the term
operator within generative grammatical theory.
Wh-operators The following example is a case of so-called "
wh-movement": : 1.
What did Bill say he wants to buy __ ? Here, "what" is an operator, binding a
phonetically empty "variable" indicated here as "__".
Quantifier raising In the generative model of the
syntax-semantics interface, a quantifier must
move to positions higher in the structure, leaving behind a
trace which it then binds. When this movement leaves the spoken word order unchanged, it is said to be "covert". : 3. Somethingx [I didn't do x] Here, "x" is the variable, and "somethingx" is the operator binding that variable.
Tough constructions The following is an example which is treated within generative grammar in terms of an invisible operator binding an invisible variable: : 4. John is easy to please. The relevant aspects of this sentence are represented as follows: : 5. John is easy [OPx to please x]. Here, "Opx" is the empty operator and "x" is the variable bound by that operator, functioning as the
object of the verb "please". Part of the reason to assume the empty operator—variable dependency in such sentences is that they exhibit sensitivity to
extraction islands. For example, the following attempt to create a similar example results in an ungrammatical sentence. The theoretical representation of the sentence is given right below, omitting, again, irrelevant details. : 6.
Bad: John is easy to decide whether to please. : 7. John is easy [Opx to decide
whether to please x] Here, "whether" creates an island for a-bar movement. This means that the operator Opx is unable to bind its variable "x", and this is thought to be the reason why the sentence is ungrammatical. One popular theoretical implementation of this is called "relativized minimality". Roughly, it states that a variable of a given kind must be bound by the closest available operator of the same kind. In (6,7), "x" can't be bound by "Opx", because there is a closer operator of the same kind as "Opx": "whether". The sentence (4) with its representation (5) is grammatically acceptable because there's no intervening operator between "Opx" and "x" which blocks the dependency in that sentence. == See also ==