Decomposing cubic graphs into isomorphic linear forests
Gal Kronenberg, Shoham Letzter, Alexey Pokrovskiy, Liana Yepremyan · arXiv (Cornell University) · 2022
A common problem in graph colouring seeks to decompose the edge set of a given graph into few similar and simple subgraphs, under certain divisibility conditions. In 1987 Wormald conjectured that the edges of every cubic graph on $4n$ vertices can be partitioned into two isomorphic linear forests. We prove this conjecture for large connected cubic graphs. Our proof uses a wide range of probabilistic tools in conjunction with intricate structural analysis, and introduces a variety of local recolouring techniques.