# Symbols:Symbolic Logic/NAND

## Logical NAND

$\uparrow$

A binary operation on two propositions.

$P \uparrow Q$ means not both $P$ and $Q$ together.

The $\LaTeX$ code for $P \uparrow Q$ is P \uparrow Q .

## Deprecated Symbols

### Sheffer Stroke

$\mid$

A binary operation on two propositions.

$P \mid Q$ means not both $P$ and $Q$ together

This is known as the Sheffer stroke.

The $\LaTeX$ code for $P \mid Q$ is P \mid Q .

### Modified Ampheck

$P \mathop {\bar \curlywedge} Q$

A binary operation on two propositions.

$P \mathop {\bar \curlywedge} Q$ means not both $P$ and $Q$ together.

The $\LaTeX$ code for $P \mathop {\bar \curlywedge} Q$ is P \mathop {\bar \curlywedge} Q .

## Also known as

The uparrow symbol $\uparrow$, when used in this context, is sometimes referred to as the Sheffer stroke, after Henry Maurice Sheffer.

However, that name properly belongs to the $\mid$ symbol.