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. (August 2012)
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.
The successor function, denoted , is a unary operator. Its domain and codomain are the natural numbers, its definition is as follows:
In many programming languages such as C, executing this operation is denoted by postfixing to the operand, i.e. the use of is equivalent to executing the assignment .
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.