We survey the literature on social networks by putting together the economics, sociological and physics/applied mathematics approaches, showing their similarities and differences. We expose, in particular, the two main ways of modeling network formation. While the physics/applied mathematics...

"A large amount of activity in the financial sector occurs in secondary financial markets, where securities are traded among investors without capital flowing to firms. The stock market is the archetypal example, which in most developed economies captures a lot of attention and resources. Is the...