This paper introduces a number of game-theoretic tools to model collusive agreements among firms in vertically differentiated markets. I firstly review some classical literature on collusion between two firms producing goods of exogenous different qualities. I then extend the analysis to a...

The seminal paper by Salant, Switzer and Reynolds (1983) showed that merger in a standard Cournot framework with linear demand and linear costs is not profitable unless a large majority of the firms are involved in the merger. However, many strategic aspects matter for firm competition such as...

This chapter surveys recent models of coalition and network formation in a unified framework. Comparisons are drawn among various procedures of network and coalition formation, involving simultaneous and sequential moves. The survey also covers models of group and network formation by farsighted...

We adopt the largest consistent set defined by Chwe [J. of Econ. Theory 63 (1994), 299-235] to predict which coalition structures are possibly stable when players are farsighted. We also introduce a refinement, the largest cautious consistent set, based on the assumption that players are...

Ordinally single-peaked preferences are distinguished from cardinally single-peaked preferences, in which all players have a similar perception of distances in some one-dimensional ordering. While ordinal single-peakedness can lead to disconnected coalitions that have a "hole" in the ordering,...

We introduce a noncooperative multilateral bargaining model for a network-restricted environment, in which players can communicate only with their neighbors. Each player strategically chooses the bargaining partners among the neighbors to buy out their communication links with upfront transfers....