Found:
negation
SEMANTICS: the logical operation in propositional logic which turns the truth value of a proposition into its opposite. Proposition Neg phi is true if and only if phi is not true:
(i) phi Neg phi 1 0 0 1The negation operator Neg is a unary connective. In syllogistic logic, negation can be an operator on terms. Thus in nobody is ill, the term nobody is considered the negation of somebody.
| LIT. | Gamut, L.T.F. (1991) |