Editing Scale-free network (section)

====Hierarchical network model====
[[Hierarchical network model]]s are, by design, scale free and have high clustering of nodes.<ref name=Rav>{{cite journal | last1 = Ravasz | first1 = E. | last2 = Barabási | year = 2003 | title =  Hierarchical organization in complex networks| journal = Phys. Rev. E | volume = 67 | issue = 2| page = 026112 | doi=10.1103/physreve.67.026112| pmid = 12636753 | arxiv = cond-mat/0206130| bibcode = 2003PhRvE..67b6112R| s2cid = 17777155 }}</ref>

The [[Iterative hierarchy|iterative]] construction leads to a hierarchical network. Starting from a fully connected cluster of five nodes, we create four identical replicas connecting the peripheral nodes of each cluster to the central node of the original cluster. From this, we get a network of 25 nodes (''N''&nbsp;=&nbsp;25).
Repeating the same process, we can create four more replicas of the original cluster – the four peripheral nodes of each one connect to the central node of the nodes created in the first step. This gives ''N''&nbsp;=&nbsp;125, and the process can continue indefinitely.