content_image/333883.jpg
<img src='content_image/333883.jpg'>

nodes of the network represent the authors, who are connected if they have co-authored at least one paper. The cond-mat collaboration dataset consists of 17628 authors with average degree 6.0 

f) The Internet at the router level (RL) . The nodes of the RL Internet network are the Internet routers. Two routers are connected if there exists a physical connection between them. Data have been gathered from the DIMES project [13]. The largest connected component of the analyzed dataset contains 493312 routers with an average degree of 3.3. 

g) The Internet at the autonomous system level (AS) . The nodes are autonomous systems which are connected if there exists a physical connection between them. An autonomous system is a collection of connected IP routing prefixes under the control of one or more network operators that presents a common, clearly defined routing policy to the Internet. Data have been gathered by the DIMES project [13]. The largest connected component of the AS Internet consists of 20556 autonomous systems with average degree 6.1. 

h) Product space of economic goods . This is the network of proximity between products according to Ref. [22]. We use a proximity threshold 0.3, and we recover similar results for 

