Be G a graph and let's assume that for every sub graph G'=(V',E' ) |E' |≤2|V' |Show you can direct the graph edges so every exit rank is at most 2.
So my idea was to say there exits at least one exit rank in every way we can direct such that it is >=3, then take the subgroup(of the vertices and the subgraph made from them) without the vertices with exit rank >=3 and try to get a contradiction but I'm getting stuck