Operator (mathematics)
（重定向自Mathematical operator）
An operator is a mapping from one vector space or module to another. Operators are of critical importance to both linear algebra and functional analysis, and they find application in many other fields of pure and applied mathematics. For example, in classical mechanics, the derivative is used ubiquitously, and in quantum mechanics, observables are represented by hermitian operators. Important properties that various operators may exhibit include linearity, continuity, and boundedness.