1 Department of Computer Science, Faculty of Science, Aarhus University, Aarhus University2 unknown
Let G = (V,E) be a graph or digraph and r : V → Z+. An r-detachment of G is a graph H obtained by ‘splitting’ each vertex ν ∈ V into r(ν) vertices. The vertices ν1,…,νr(ν) obtained by splitting ν are called the pieces of ν in H. Every edge uν ∈ E corresponds to an edge of H connecting some piece of u to some piece of ν. Crispin Nash-Williams  gave necessary and sufficient conditions for a graph to have a k-edge-connected r-detachment. He also solved the version where the degrees of all the pieces are specified. In this paper, we solve the same problems for directed graphs. We also give a simple and self-contained new proof for the undirected result. This work is dedicated to the memory of Crispin Nash-Williams.
Journal of Graph Theory, 2003, Vol 43, Issue 1, p. 67-77