A maximum or minimum value of a real-valued function. (Cf. Maximum and minimum points.) In the calculus of variations the term "extremum" is also used in the study of greatest or smallest values of a functional.
Cf. also Maximum and minimum of a function.
Extremum. A.B. Ivanov (originator), Encyclopedia of Mathematics. URL: http://www.encyclopediaofmath.org/index.php?title=Extremum&oldid=18848