A \(k\)-circuit is a directed cycle of length \(k\). In this paper, we completely solve the problem of finding maximum packings and minimum coverings of \(\lambda\)-fold complete bipartite symmetric digraphs with \(6\)-circuits.
Citation
Hung-Chih Lee. Packing and Covering Complete Bipartite Multidigraphs with \(6\)-circuits[J], Ars Combinatoria, Volume 097. 511-522. .