Definition:Logical NAND

Definition
NAND (that is, "not and"), is a binary connective, written symbolically as $$p \uparrow q$$, whose behaviour is as follows:


 * $$p \uparrow q$$ is defined as: "$$p$$ is false and $$q$$ is false."

"$$p \uparrow q$$" is voiced "$$p$$ nand $$q$$".

The symbol $$\uparrow$$ is known as the "Sheffer stroke", named after Henry Sheffer, who proved an important result about this operation.

Complement
The complement of $$\uparrow$$ is the conjunction operator.

Truth Table
The truth table of $$p \uparrow q$$ and its complement is as follows:

Notational Variants
Alternative symbols that mean the same thing as $$p \uparrow q$$ are also encountered:


 * $$p \ \texttt{NAND} \ q$$;
 * $$p \ | \ q$$, also sometimes referred to as the Sheffer stroke;
 * $$p \bar \curlywedge q$$, this notation originating with Charles Sanders Peirce.