A set-like object in which order is ignored, but multiplicity is explicitly significant. Therefore, multisets {1,2,3} and {2,1,3} are equivalent, but {1,1,2,3} and {1,2,3} differ. The number of multisets of length k on n symbols is called n multichoose k, denoted ((n; k)).

See also

Aggregate, Ball Picking, Binomial Coefficient, Choose, Collection, Combination, List, Multichoose, Multinomial Coefficient, Partially Ordered Multiset, Permutation, Set, String

Explore with Wolfram|Alpha


Skiena, S. Implementing Discrete Mathematics: Combinatorics and Graph Theory with Mathematica. Reading, MA: Addison-Wesley, p. 12, 1990.

Referenced on Wolfram|Alpha


Cite this as:

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

Subject classifications