Montague adds two other pieces of notation to his language: ∧ and  ∨. The expression ∧λx[Fx] represents a function from worlds to sets of individuals. Given a possible world w, ∧λx[Fx] represents a function that takes w to the extension of λx[Fx]. The operator ∨ takes expressions of the form ∧λx[Fx] ‘down’ to their extensions at the world in which the expression is being evaluated. For example, the extension of ∨∧λx[Fx] at w is just the same as the extension of λx[Fx] at w.