for negation in linguistics, see affirmation and negation. for other uses, see negation (disambiguation).
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in logic, negation, also called the logical complement, is an operation that takes a proposition to another proposition "not ", written , which is interpreted intuitively as being true when is false, and false when is true. negation is thus a unary (single-argument) logical connective. it may be applied as an operation on notions, propositions, truth values, or semantic values more generally. in classical logic, negation is normally identified with the truth function that takes truth to falsity and vice versa. in intuitionistic logic, according to the brouwer–heyting–kolmogorov interpretation, the negation of a proposition is the proposition whose proofs are the refutations of .