 In classical logic, the semantic principle of bivalence is assumed, saying that a formula has exactly one of two semantic values, namely either the value T[rue] or the value F[alse] (1 or 0), but not both. Negation, \(\osim \), is semantically characterized by the unary function \(f_{\osim }\) on the set \(\{1, 0\}\), defined by the following truth table: