ringel_conjecture
For any tree T with n edges, the complete graph K2n+1 decomposes into
2n+1 edge-disjoint copies of T.
A "copy" of T is the image T.map(fi) of T under a vertex embedding
fi:V↪Fin(2n+1); the copies are pairwise edge-disjoint
and together cover every edge of K2n+1.