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# Logical negation

**Logical negation** is an operation on one logical value, typically the value of a proposition, that produces a value of *true* when its operand is false and a value of *false* when its operand is true.

A truth table for also written appears below:

The negation of a proposition may be found notated in various ways in various contexts of application, often merely for typographical convenience. Among these variants are the following:

bar | |

tilde | |

prime complement | |

bang |

A logical graph for is shown below:

The traversal string of this graph is The proposition may be taken as a Boolean function having the abstract type where is interpreted in such a way that means and means

A Venn diagram for indicates the region where is true by means of a distinctive color or shading. In this case the region is a single cell, as shown below:

## Resources

## Document history

Portions of the above article were adapted from the following sources under the GNU Free Documentation License, under other applicable licenses, or by permission of the copyright holders.