Figure 3
A network representing a circular distance. A circular distance d on the set {u, v, ..., z} for which NeighborNet using only the Q-criterion employed in NJ to cluster elements would be inconsistent. Distances are given by shortest paths in the network. The pairs u, v and x, y would be clustered together first and then the pair z, w. However it is not hard to show that z and w are not adjacent in any ordering of {u, v, ..., z} that is compatible with d.