The co-author model is introduced by Jackson and Wolinsky (1996, Journal of Economic Theory) as a typical example of the models of network formation. In this note, we study which network is pairwise stable and/or stochastically stable when the number of players is four.

Jackson and Watts (2002, J Econ Theory) study a dynamic process of network formation assuming that each player is myopic. In this note, we study the same dynamic process but assume that each player is farsighted. In particular, we consider a finite-horizon version of such a dynamic process in a...

Many goods have network externalities. When the number of agents possessing such goods is small, the agents may not gain sufficient utility from the goods. Agents then have an incentive to delay their purchasing decisions. Such delays have negative effects on the agents' utility, so equilibrium...

We experimentally study the effect of a third-person enforcement on a one-shot prisoner’s dilemma game played by two persons, with whom the third person plays repeated prisoner’s dilemma games. We find that when the third person can observe these two persons’ play, the possibility of the...

So-called “search equilibrium models” typically have multiple equilibria. In almost all studies on these models, only steady states are considered mainly because it is difficult to find non-stationary equilibria. This difficulty does not disappear even if we consider finite-horizon...

The Dutta-Ray solution and the Shapley value are two well-known examples of population-monotonic solutions on the domain of convex games. We provide a new formula for the Dutta-Ray solution from which population-monotonicity immediately follows. Then we define a new family of...

We show that the nucleolus is not aggregate-monotonic on the domain of convex games, and that this lack of monotonicity holds even if there are as few as four agents.

On the domain of convex games, many desirable properties of solutions are compatible and there are many single-valued solutions that are intuitively appealing. We establish some interesting logical relations among properties of single-valued solutions. In particular, we introduce a new property,...