Credit: Santa Fe Institute image courtesy Hébert-Dufresne, Allard, and Grochow
Image caption: The authors tested their new Onion Decomposition on, among other networks, the stanford.edu World Wide Web network domain. In the first layer (left), they discovered an unexpected subnetwork structure — some 8,500 nodes with two connections (~3% of the entire network) joined in chain-like fashion, a deviation from the expected centralized tree-like structure; such surprising structures seemed to occur on all scales within the Stanford network, they note. In the sixth layer they found a more typical, highly centralized community structure suggesting many groups governed by only a few nodes.