Unary function

A unary function is a function that takes one argument. A unary operator belongs to a subset of unary functions, in that its range coincides with its domain.

Examples

The successor function is a unary operator. Its domain and codomain are the natural numbers, its definition is as follows:

$${\begin{aligned}\operatorname {succ} &:\mathbb {N} \longrightarrow \mathbb {N} \\\operatorname {succ} (n)&:=n+1\end{aligned}}$$

In many programming languages such as C, this operation is denoted postfix as ${\mathrel {+{+}}}$, i.e. $\operatorname {succ} (n)=n{\mathrel {+{+}}}$.

Many of the elementary functions are unary functions, in particular the trigonometric functions, logarithm with a pre-specified base, exponentiation to a pre-specified power or of a pre-specified base, and hyperbolic functions are unary.

See also

• Arity
• Binary function
• Binary operator
• List of mathematical functions
• Ternary operation
• Unary operation

References

• Foundations of Genetic Programming