Operator topic

In mathematics, an operator is a function which operates on (or modifies) another function. Often, an "operator" is a function which acts on functions to produce other functions (the sense in which Oliver Heaviside used the term); or it may be a generalization of such a function, as in linear algebra, where some of the terminology reflects the origin of the subject in operations on the functions which are solutions of differential equations. An operator can perform a function on any number of... full article at wikipedia