Essays on Coalition Formation Theory

The thesis is a contribution to Coalition Formation Theory. Coalition formation theory is the collection of disciplines and mathematical tools which deals with the analysis of coalition formation processes. A coalition formation process is a process by which agents get together to coordinate their actions in order to achieve shared goals. Coalition formation is an important and recurrent pattern in human behavior and many social phenomena can be studied in terms of coalition formation processes. Examples are: cartel formation, environmental agreements, political party formation, lobbying and the of a local public good. The thesis provide a new tool to analyse coalition formation processes and to predict the behaviour of the agents involved in the processes. From one side, our new tool connects and generalizes different existing tools; from another side it is able to provide predictions even when the other tools fails

Myopic Oligopoly Pricing

This paper examines capacity-constrained oligopoly pricing with sellers who seek myopic improvements. We employ the Myopic Stable Set solution concept and establish the existence of a unique pure-strategy price solution for any given level of capacity. This solution is shown to coincide with the set of pure-strategy Nash equilibria when capacities are large or small. For an intermediate range of capacities, it predicts a price interval that includes the mixed-strategy support. This stability concept thus encompasses all Nash equilibria and o ers a pure-strategy solution when there is none in Nash terms. It particularly provides a behavioral rationale for di erent pricing patterns, including Edgeworth price cycles and states of hypercompetition with supply shortages. We also analyze the impact of a change in firm size distribution. A merger among the biggest firms may lead to more price dispersion as it increases the maximum and decreases the minimum myopically stable price

Decreasing Incomes Increase Selfishness

We use a controlled laboratory experiment to study the causal impact of income de-creases within a time period on redistribution decisions at the end of that period, in an environment where we keep fixed the sum of incomes over the period. First, we inves-tigate the effect of a negative income trend (intra-personal decrease), which means a decreasing income compared to one’s recent past. Second, we investigate the effect of a negative income trend relative to the income trend of another person (inter-personal decrease). If intra-personal or inter-personal decreases create dissatisfaction for an individual, that person may become more selfish to obtain compensation. We formal-ize both effects in a multi-period model augmenting a standard model of inequality aversion. Overall, conditional on exhibiting sufficiently-strong social preferences, we find that individuals indeed behave more selfishly when they experience decreasing in-comes. While many studies examine the effect of income inequality on redistribution decisions, we delve into the history behind one’s income to isolate the effect of income changes

The Last will be First, and the First Last: Segregation in Societies with Relative Payoff Concerns

This article studies coalition formation among individuals who differ in productivity. We consider egalitarian societies in which coalitions split their surplus equally and individualistic societies in which coalitions split their surplus according to productivity. Preferences of coalition members depend on their material pay-offs, but are also influenced by relative pay-off concerns. The stable partitions in both egalitarian and individualistic societies are segregated, i.e., individuals with adjacent productivities form coalitions. If some individuals are not part of a productive coalition, then these are the least productive ones for egalitarian societies and the most productive ones for individualistic societies

The Myopic Stable Set for Social Environments

© 2019 The Econometric Society We introduce a new solution concept for models of coalition formation, called the myopic stable set (MSS). The MSS is defined for a general class of social environments and allows for an infinite state space. An MSS exists and, under minor continuity assumptions, it is also unique. The MSS generalizes and unifies various results from more specific applications. It coincides with the coalition structure core in coalition function form games when this set is nonempty; with the set of stable matchings in the Gale–Shapley matching model; with the set of pairwise stable networks and closed cycles in models of network formation; and with the set of pure strategy Nash equilibria in pseudo-potential games and finite supermodular games. We also characterize the MSS for the class of proper simple games.status: publishe

Bertrand competition with asymmetric costs: a solution in pure strategies

© 2019, The Author(s). We consider a Bertrand duopoly with homogeneous goods and we allow for asymmetric marginal costs. We derive the Myopic Stable Set in pure strategies as introduced by Demuynck et al. (Econometrica 87:111–138, 2019). In contrast to the set of Nash equilibria, the unique Myopic Stable Set can be easily characterized in closed form and it provides an intuitive set-valued prediction.status: publishe

Bertrand competition with asymmetric costs: a solution in pure strategies

We consider a Bertrand duopoly with homogeneous goods and we allow for asymmetric marginal costs. We derive the Myopic Stable Set in pure strategies as introduced by Demuynck et al. (Econometrica 87:111-138, 2019). In contrast to the set of Nash equilibria, the unique Myopic Stable Set can be easily characterized in closed form and it provides an intuitive set-valued prediction