Topic summary
Total function
Extracted from the Wikipedia article Partial function.
In mathematics, a partial functionf from a setX to a set Y is a function from a subsetS of X (possibly the whole X itself) to Y. The subset S, that is, the domain of f viewed as a function, is called the domain of definition or natural domain of f. If S equals X, that is, if f is defined on every element in X, then f is said to be a total function.