Title
Universal and Near-Universal Cycles of Set Partitions
Abstract
We study universal cycles of the set P(n, k) of k -partitions of the set [n] := {1, 2,..., n} and prove that the transition digraph associated with P(n, k) is Eulerian. But this does not imply that universal cycles (or ucycles) exist, since vertices represent equivalence classes of partitions. We use this result to prove, however, that ucycles of P(n, k) exist for all n >= 3 when k = 2. We reprove that they exist for odd n when k = n - 1 and that they do not exist for even n when k = n 1. An infinite family of (n, k) for which ucycles do not exist is shown to be those pairs for which {(n-2)(k-2)} is odd (3 <= k < n 1). We also show that there exist universal cycles of partitions of [n] into k subsets of distinct sizes when k is sufficiently smaller than n, and therefore that there exist universal packings of the partitions in P(n, k). An analogous result for coverings completes the investigation.
Year
Venue
Field
2015
ELECTRONIC JOURNAL OF COMBINATORICS
Discrete mathematics,Combinatorics,Vertex (geometry),Eulerian path,Equivalence class,Digraph,Mathematics
DocType
Volume
Issue
Journal
22
4.0
ISSN
Citations 
PageRank 
1077-8926
0
0.34
References 
Authors
6
4
Name
Order
Citations
PageRank
Zach Higgins100.34
Elizabeth Kelley200.34
Bertilla Sieben300.34
Anant P. Godbole49516.08