# Multiset

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A multiset is a collection of unordered objects.

Unlike sets, elements of multisets need not be distinct.

## Multiset coefficientEdit

The number of multisets of size k taken from a set of cardinality n is denoted by the multiset coefficient, denoted by $\scriptstyle\left(\!\!{n\choose k}\!\!\right)$, and is equal to:

$\left(\!\!{n\choose k}\!\!\right) = {n + k - 1 \choose k}={n+k-1 \choose n-1}$.