Rainbow spanning tree decompositions in complete graphs colored by cyclic 1-factorizations

Brualdi and Hollingsworth conjectured in Brualdi and Hollingsworth (1996) that in any complete graph K2n, n≥3, which is properly colored with 2n−1 colors, the edge set can be partitioned into n edge disjoint rainbow spanning trees (where a graph is said to be rainbow if its edges have distinct colors). Constantine (2002) strengthened this conjecture asking the rainbow spanning trees to be pairwise isomorphic. He also showed an example satisfying his conjecture for every 2n∈{2s:s≥3}∪{5⋅2s,s≥1}. Caughmann, Krussel and Mahoney (2017) recently showed a first infinite family of edge colorings for which the conjecture of Brualdi and Hollingsworth can be verified. In the present paper, we extend this result to all edge-colorings arising from cyclic 1-factorizations of K2n constructed by Hartman and Rosa (1985). Finally, we remark that our constructions permit to extend Constatine's result also to all 2n∈{2sd:s≥1,d>3odd}.