Found:

Operator

**SYNTAX: **element, such as a **quantifier** (i) or a **wh-phrase** (ii), which A-bar binds a **variable** (x) at **LF** (see
**A-bar binding**):

(i) Mary lovessomeoneLF: someone x, Mary loves x (ii)Whodoes Mary love? LF: for which x, Mary loves x

**SEMANTICS: **a **logical constant**
(O) which is (usually) prefixed to a **formula** phi
in order to produce a new formula Ophi. The interpretation of this formula is a
compositional function of the interpretation of phi. Negation is a truth-functional
operator, which operates on the truth value of the proposition it is combined with.
Modal operators (like necessarily) and tense operators (like *it has been the case
that*) are not truth functional, because their interpretation does not solely
depend on the truth value of the formula with which they combine, but also on the
possible world or moment of time with respect to which the whole sentence is evaluated.

LIT. | Chomsky, N. (1981) Gamut, L.T.F. (1991) |