This is a disambiguation page: a list of articles associated with the same title. If an internal link referred you to this page, you may wish to change the link to point directly to the intended article.
As a mathematical term, "function" was coined by Gottfried Leibniz in 1694, to describe a quantity related to a curve, such as a curve's slope at a specific point of a curve.
The squaring function is the inverse of the non-negative square root function.
The number of computable functions from integers to integers is countable, because the number of possible algorithms is. The number of all functions from integers to integers is higher: the same as the cardinality of the real numbers.