Complex scale-free networks with tunable power-law exponent and clustering

• Main Authors: Colman, ER, Rodgers, GJ
• Format: Journal Article
• Language: English
• Published: 28-07-2013
• Subjects: Computer Science - Social and Information Networks; Physics - Physics and Society
• DOI: 10.48550/arxiv.1307.7389

We introduce a network evolution process motivated by the network of
citations in the scientific literature. In each iteration of the process a node
is born and directed links are created from the new node to a set of target
nodes already in the network. This set includes $m$ "ambassador" nodes and $l$
of each ambassador's descendants where $m$ and $l$ are random variables
selected from any choice of distributions $p_{l}$ and $q_{m}$. The process
mimics the tendency of authors to cite varying numbers of papers included in
the bibliographies of the other papers they cite. We show that the degree
distributions of the networks generated after a large number of iterations are
scale-free and derive an expression for the power-law exponent. In a particular
case of the model where the number of ambassadors is always the constant $m$
and the number of selected descendants from each ambassador is the constant
$l$, the power-law exponent is $(2l+1)/l$. For this example we derive
expressions for the degree distribution and clustering coefficient in terms of
$l$ and $m$. We conclude that the proposed model can be tuned to have the same
power law exponent and clustering coefficient of a broad range of the
scale-free distributions that have been studied empirically.