The organization of individuals into networks and groups is of fundamental importance in many social and economic interactions. Examples range from networks of personal contacts used to obtain information about job opportunities to the formation of trading partnerships, alliances, cartels, and...

We analyze the formation of networks among individuals. In particular, we examine the existence of networks that are stable against changes in links by any coalition of individuals. We show that to investigate the existence of such strongly stable networks one can restrict focus on a...