SEMANTICS: a sentence which is false under all circumstances, i.e. for every
assignment of values to its basic expressions. A sentence of
propositional logic is a contradiction
when it is false for every possible assignment of truth values to the propositional
letters of that sentence.
For example, the formula p & Neg p is a contradiction of propositional logic. A
sentence of predicate logic is a
contradiction when it is false for every possible denotation of the variables and
individual and predicate constants that it contains. For example, the formula
All(x)[ P(x) & Neg P(x) ] is a contradiction of predicate logic.
|LIT.||Gamut, L.T.F. (1991)|