Unary operation

In mathematics, a unary operation is an operation with only one operand, i.e. a single input. This is in contrast to binary operations, which use two operands. An example is any function⁠ $f:A ightarrow A$ ⁠, where $A$ is a set; the function ⁠ $f$ ⁠ is a unary operation on $A$ .

Common notations are prefix notation (e.g. negation $\neg$ , additive inverse $-$ ), postfix notation (e.g. factorial $n!$ ), functional notation (e.g. $sin x$ or $sin(x)$ ), and superscripts (e.g. transpose $A$ ). Other notations exist as well, for example, in the case of the square root, a horizontal bar extending the square root sign over the argument can indicate the extent of the argument.