In number theory and combinatorics, a multipartition of a positive integer n is a way of writing n as a sum, each element of which is in turn an integer partition. The concept is also found in the theory of Lie algebras.
An r-component multipartition of an integer n is an r-tuple of partitions û<sup>(1)</sup>, ..., û<sup>(r)</sup> where each û<sup>(i)</sup> is a partition of some a<sub>i</sub> and the a<sub>i</sub> sum to n. The number of r-component multipartitions of n is denoted P<sub>r</sub>(n). Congruences for the function P<sub>r</sub>(n) have been studied by A. O. L. Atkin.