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. (August 2012)
In mathematics, a unary function is a function that takes one argument. A unary operator belongs to a subset of unary functions, in that its codomain coincides with its domain. In contrast, a unary function's domain need not coincide with its range.
The successor function, denoted , is a unary operator. Its domain and codomain are the natural numbers; its definition is as follows:
In some programming languages such as C, executing this operation is denoted by postfixing
++ to the operand, i.e. the use of
n++ is equivalent to executing the assignment .
Many of the elementary functions are unary functions, including the trigonometric functions, logarithm with a specified base, exponentiation to a particular power or base, and hyperbolic functions.