The number of "arrangements" in an ordering of n items is given by either a combination (order is ignored) or a permutation (order is significant).

An ordering (or order) is also a method for choosing the order in which elements are placed (i.e., a sorting function).

The Wolfram Language function Ordering[p] gives the inverse permutation of a given permutation p.

See also

Arrangement, Combination, Cutting, Derangement, Inverse Permutation, Lexicographic Order, Monomial Order, Ordering Axioms, Partial Order, Permutation, Sorting, Total Order, Transposition Order, Well Ordered Set

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Cite this as:

Weisstein, Eric W. "Ordering." From MathWorld--A Wolfram Web Resource.

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