| 讲座简介： | We investigate informal risk sharing using a dynamic network game model. In each round, a randomly selected agent experiences a negative shock, and the agent's friends decide whether to provide assistance. Assuming that agents have concave utility functions, we prove a version of the Folk Theorem. Our analysis shows that a pair of agents are able to help each other in all relevant rounds of a subgame perfect Nash equilibrium if and only if this connection is a part of a subgraph, in which each agent has a number of friends that is neither too low nor too high. We refer to this type of a subgraph as an inner-core. Connected inner-cores can be understood as communities. Although optimization problems related to inner-cores are generally NP-hard, we are able to perform several natural comparative statics. |
