The logical connective combining two statements, truth values, or formulas P and Q in such a way that the outcome is true only if either P or Q or both is false (see table). The NAND operation may be represented by the Sheffer stroke, |, or by Δ‎. P | Q is just the negation of P ∧ Q, hence the name (see AND operation).

The NAND operation is of particular significance to computer designers since any Boolean expression can be realized by an expression using only the NAND operation. In practical terms, circuits can be built using only NAND gates.

NAND operation. Truth table