Article
Keywords:
even graph; closed trail; graph arbitrarily decomposable into closed trails; bipartite graph
Summary:
Let ${\rm Lct}(G)$ denote the set of all lengths of closed trails that exist in an even graph $G$. A sequence $(t_1,\dots ,t_p)$ of elements of ${\rm Lct}(G)$ adding up to $|E(G)|$ is $G$-realisable provided there is a sequence $(T_1,\dots ,T_p)$ of pairwise edge-disjoint closed trails in $G$ such that $T_i$ is of length $t_i$ for $i=1,\dots ,p$. The graph $G$ is arbitrarily decomposable into closed trails if all possible sequences are $G$-realisable. In the paper it is proved that if $a\ge 1$ is an odd integer and $M_{a,a}$ is a perfect matching in $K_{a,a}$, then the graph $K_{a,a}-M_{a,a}$ is arbitrarily decomposable into closed trails.
References:
[4] Chou, Ch.-Ch., Fu, Ch.-M., Huang, W.-Ch.:
Decomposition of $K_{n,m}$ into short cycle. Discrete Math. 197/198 (1999), 195-203.
MR 1674862
[6] Cichacz, S., Przybyło, J., Wo'zniak, M.:
Decompositions of pseudographs into closed trails of even sizes. Discrete Math., doi:10.1016/j.disc.2008.04.024.
DOI 10.1016/j.disc.2008.04.024
[7] Horňák, M., Kocková, Z.:
On complete tripartite graphs arbitrarily decomposable into closed trails. Tatra Mt. Math. Publ. 36 (2007), 71-107.
MR 2378742