In mathematics, a smooth maximum of an indexed family x1, ..., xn of numbers is a smooth approximation to the maximum function max ( x 1 , … , x n ) , {\displaystyle \max(x_{1},\ldots ,x_{n}),} meaning a parametric family of functions m α ( x 1 , … , x n ) {\displaystyle m_{\alpha }(x_{1},\ldots ,x_{n})} such that for every α, the function m α {\displaystyle m_{\alpha }} is smooth, and the family converges to the maximum function m α → max {\displaystyle m_{\alpha }\to \max } as α → ∞ {\displaystyle \alpha \to \infty } . The concept of smooth minimum is similarly defined. In many cases, a single family approximates both: maximum as the parameter goes to positive infinity, minimum as the parameter goes to negative infinity; in symbols, m α → max {\displaystyle m_{\alpha }\to \max } as α → ∞ {\displaystyle \alpha \to \infty } and m α → min {\displaystyle m_{\alpha }\to \min } as α → − ∞ {\displaystyle \alpha \to -\infty } . The term can also be used loosely for a specific smooth function that behaves similarly to a maximum, without necessarily being part of a parametrized family.