Four Ways to Change Coalitions: Agents, Dependencies, Norms and Internal Dynamics

We introduce a new formal approach to social networks in order to distinguish four ways in which coalitions change.First, the agents in the network change. Second, dependencies among the agents change, for example due to addition or removal of powers and goals of the agents. Third, norms can introduce normative dependencies for obligations and prohibitions. Fourth, coalitions can change due to internal processes. We propose a number of stability measures to identify each one of the four proposed sources of coalitions ’dynamics and the consequences they induce on the stability of coalitions.