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Minimum


The smallest value of a set, function, etc. The minimum value of a set of elements A={a_i}_(i=1)^N is denoted minA or min_(i)a_i, and is equal to the first element of a sorted (i.e., ordered) version of A. For example, given the set {3,5,4,1}, the sorted version is {1,3,4,5}, so the minimum is 1. The maximum and minimum are the simplest order statistics.

The minimum value of a variable x is commonly denoted x_(min) (cf. Strang 1988, pp. 286-287 and 301-303) or x_(min) (Golub and Van Loan 1996, p. 84). In this work, the convention x_(min) is used.

The minimum of a set of elements is implemented in the Wolfram Language as Min[list] and satisfies the identities

min(x,x)=x
(1)
min(x,y)=min(y,x).
(2)
Minimum

A continuous function may assume a minimum at a single point or may have minima at a number of points. A global minimum of a function is the smallest value in the entire range of the function, while a local minimum is the smallest value in some local neighborhood.

For a function f(x) which is continuous at a point x_0, a necessary but not sufficient condition for f(x) to have a local minimum at x=x_0 is that x_0 be a critical point (i.e., f(x) is either not differentiable at x_0 or x_0 is a stationary point, in which case f^'(x_0)=0).

The first derivative test can be applied to continuous functions to distinguish minima from maxima. For twice differentiable functions of one variable, f(x), or of two variables, f(x,y), the second derivative test can sometimes also identify the nature of an extremum. For a function f(x), the extremum test succeeds under more general conditions than the second derivative test.

Definite integral include

int_0^1min(x,1-x)dx=1/4
(3)
int_0^1(min(x,1-x))/(max(x,1-x))dx=2ln2-1.
(4)

See also

Conjugate Gradient Method, Critical Point, Extremum, First Derivative Test, Global Maximum, Inflection Point, Local Maximum, Maximum, Method of Steepest Descent, Midrange, Order Statistic, Saddle Point, Second Derivative Test, Stationary Point Explore this topic in the MathWorld classroom

Related Wolfram sites

http://functions.wolfram.com/ElementaryFunctions/Min/

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References

Abramowitz, M. and Stegun, I. A. (Eds.). Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, 9th printing. New York: Dover, p. 14, 1972.Brent, R. P. Algorithms for Minimization Without Derivatives. Englewood Cliffs, NJ: Prentice-Hall, 1973.Golub, G. and Van Loan, C. Matrix Computations, 3rd ed. Baltimore, MD: Johns Hopkins University Press, 1996.Nash, J. C. "Descent to a Minimum I-II: Variable Metric Algorithms." Chs. 15-16 in Compact Numerical Methods for Computers: Linear Algebra and Function Minimisation, 2nd ed. Bristol, England: Adam Hilger, pp. 186-206, 1990.Niven, I. Maxima and Minima without Calculus. Washington, DC: Math. Assoc. Amer., 1982.Press, W. H.; Flannery, B. P.; Teukolsky, S. A.; and Vetterling, W. T. "Minimization or Maximization of Functions." Ch. 10 in Numerical Recipes in FORTRAN: The Art of Scientific Computing, 2nd ed. Cambridge, England: Cambridge University Press, pp. 387-448, 1992.Strang, G. Linear Algebra and its Applications, 3rd ed. Philadelphia, PA: Saunders, 1988.Tikhomirov, V. M. Stories About Maxima and Minima. Providence, RI: Amer. Math. Soc., 1991.

Referenced on Wolfram|Alpha

Minimum

Cite this as:

Weisstein, Eric W. "Minimum." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Minimum.html

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