Fig. 3.

Examples of tree topologies including the two extreme forms. They are all composed of 11 nodes and 10 edges. Leaf nodes are indicated in blue, and all other nodes are red. The MST on the left is known as a line-like tree with the lowest leaf number which is 2, a highest diameter which is 10 and low tree hierarchy. The MST on the right is known as a star-like tree with the highest leaf number which is 10, a lowest diameter which is 2 and high tree hierarchy. The MST in the middle is an intermediate configuration between these two extremes with the leaf number which is 6. (A color version of this Fig. can be viewed online.)