Generalizing inplace multiplicity identities for integer compositions

Abstract

In a recentpaper, the authors gave two new identities for compositions, or ordered partitions, of integers. These identities were based on closely-related integer partition functions which have recently been studied. In the process, we also extensively generalized both of these identities. Since then, we asked whether one could generalize one of these results even further by considering compositions in which certain parts could come from t kinds (rather than just two kinds, which was the crux of the original result). In this paper, we provide such a generalization. A straightforward bijective proof is given and generating functions are provided for each of the types of compositions which arise. We close by brie y mentioning some arithmetic properties satised by the functions which count such compositions.

Key words: Composition, partition, inplace, generating function.