Fig. 10

Binary tree-based unrooted phylogenetic network N^u on X = {x₁,x₂ x₃,x₄}. The corresponding support tree is highlighted in bold. N^u-x_i is not tree-based for i = 1, …,4, because there is no spanning tree in N^u-x_i whose leaf set is equal to X∖{x_i} (Figure taken from [5])