Foundations of neo-Bayesian statistics

We study an axiomatic model of preferences, which contains as special cases Subjective Expected Utility, Choquet Expected Utility, Maxmin and Maxmax Expected Utility and many other models. First, we give a complete characterization of the class of functionals representing these preferences. Then, we show that any such functional can be represented as a Choquet integral

where is the canonical mapping from the space of bounded Σ-measurable functions into the space of weak^*-continuous affine functions on a weak*-compact, convex set of probability measures on Σ. Conversely, any preference relation defined by means of such functionals satisfies the axioms of the model we study. Different properties of the capacity give rise to different models. Our result shows that the idea of Choquet integration is general enough to embrace all the models mentioned above. In doing so, it widens the range of applicability of well-known procedures in robust statistics theory such as the Neyman–Pearson lemma for capacities [P.J. Huber, V. Strassen, Minimax tests and the Neyman–Pearson lemma for capacities, Ann. Statist. 1 (1973) 251–263], Bayes' theorem for capacities [J.B. Kadane, L. Wasserman, Bayes' theorem for Choquet capacities, Ann. Statist. 18 (1990) 1328–1339] or of results like the Law of Large numbers for capacities [F. Maccheroni, M. Marinacci, A strong law of large numbers for capacities, Ann. Probab. 33 (2005) 1171–1178].     

A Theory of Endogenous Coalition Structures

Consider an environment with widespread externalities, and suppose that binding agreements can be written. We study coalition formation in such a setting. Our analysis proceeds by defining on a partition function an extensive-form bargaining game. We establish the existence of a stationary subgame perfect equilibrium for such a game. Our main results are concerned with the characterization of equilibriumcoalition structures. We develop an algorithm that generates (under certain conditions) an equilibrium coalition structure. Our characterization results are especially sharp forsymmetricpartition functions. In particular, we provide a uniqueness theorem and apply our results to a Cournot oligopoly.Journal of Economic LiteratureClassification Numbers: C71, C72, C78, D62.     

Ultimatum Bargaining Behavior in Israel, Japan, Slovenia, and the United States: A Social Utility Analysis

We explain the main features of the results of the four-country ultimatum bargaining experiments of Roth et al. (1991), Amer. Econom. Rev.81, 1068–1095) by a social utility model. The specification of social utility of a player has two parts: a linear combination of the monetary payoffs of the proposer and the responder and payoff uncertainty. We find that, on average, responders have negative regard for proposers' earnings in all countries. Proposers have negative regard for responders' monetary earnings in countries where responders have high negative regard for proposers' earnings (USA and Slovenia). In countries where responders have low negative regard for proposers' earnings (Israel and Japan), proposers are expected payoff maximizers. Journal of Economic Literature Classification Numbers: A13, C19, C44, C72, C92, D63, D64.     

Nonconvex n-person bargaining: efficient maxmin solutions

Summary. This paper provides an axiomatic characterization of a family of so-called efficient maxmin solutions which can be seen as generalizations of the Kalai-Smorodinsky solution to nonconvex n-person bargaining problems. Moreover, it is shown that even though there are several efficient maxmin solutions for some bargaining problems, there is typically a unique efficient maxmin solution. Received: February 15, 2001; revised version: November 14, 2001     

Remarks on the application of statistical games to technological development forecasting

This work presents the probability of determining a quantitative forecast of technological development S(t) defined by a set m of parameters S⁽¹⁾(t),S⁽²⁾(t),…,S^(m)(t), based on statistical game theory. Assuming that the coordinates S⁽ⁱ⁾(t) (i = 1, 2,…,m) of a forecasted vector S(t) are stochastic processes with given probabilistic characteristics, a formula of a function forecasting the value of a coordinate S⁽ⁱ⁾(t) of this vector can be obtained. This formula permits to determine a vector of forecasts _τT(x) of technological development S(t) at a given moment t = τ+T.     

Subbalanced games and bargaining sets

Summary. In defining a bargaining set, it is desirable to require that a counterobjecting coalition has a non-empty intersection with the objecting coalition. We refer to this as the intersection property and define a bargaining set, MB ₁, that imposes this property on a variant of the bargaining set defined by Vohra (1991). To study the existence of MB ₁, a new version of the KKM theorem is proposed and the concept of a subbalanced game is introduced. We also provide conditions for the non-emptiness of MB ₂, a bargaining set introduced by Zhou (1994) which imposes the additional restriction that the objecting coalition not be a subset of the counterobjecting coalition.Received: 9 December 2002, Revised: 6 December 2004, JEL Classification Numbers: C71. Correspondence to: Chih ChangThe authors are very grateful to a referee who proposes many helpful comments on both substantive matters and exposition which much improve the paper.     

Pricing rules and Arrow–Debreu ambiguous valuation

This paper considers pricing rules of single-period securities markets with finitely many states. Our main result characterizes those pricing rules C that are super-replication prices of a frictionless and arbitrage-free incomplete asset structure with a bond. This characterization relies on the equivalence between the sets of frictionless securities and securities priced by C. The former captures securities without bid-ask spreads, while the second captures the class of securities where, if some of its delivers is replaced by a higher payoff, then the resulting security is characterized by a higher value priced by C. We also analyze the special case of pricing rules associated with securities markets admitting a structure of basic assets paying one in some event and nothing otherwise. In this case, we show that the pricing rule can be characterized in terms of capacities. This Arrow–Debreu ambiguous state price can be viewed as a generalization for incomplete markets of Arrow–Debreu state price valuation. Also, some interesting cases are given by pricing rules determined by an integral w.r.t. a risk-neutral capacity. For instance, incomplete markets of Arrow securities and a bond are revealed by a Choquet integral w.r.t. a special risk-neutral capacity.     

The separability principle in bargaining

Summary. We investigate the implications of the separability principle in the context of bargaining. For two bargaining problems with the same population, suppose that there is a subgroup of agents who receive the same payoffs in both bargaining problems. Moreover, if we imagine the departure of this subgroup with their payoffs, then the remaining agents face the same opportunities in both bargaining problems. The separability principle requires that under these hypotheses, the remaining agents should receive the same payoffs in both bargaining problems. We begin with investigating the logical relations between separability and two other axioms, contraction independence and consistency. Then, we establish characterizations of the Nash and egalitarian solutions on the basis of separability. Received: 12 August 2002, Revised: 22 March 2004, JEL Classification Numbers: C71, C78.Youngsub Chun: This work was supported by the Brain Korea 21 Project in 2003. I am grateful to William Thomson, a referee, and an associate editor for their valuable comments.     

The Biodiversity Bargaining Problem

We employ cooperative bargaining theory and Nash’s ‘rational threats’ idea to cast light on the biodiversity bargaining problem. The problem of global environmental negotiations is argued to be of the nature of a bargaining problem, in which bargainers must agree on the distribution of cooperative surplus in order to move to the bargaining frontier. We discuss the importance of both efficiency (bargaining frontier) and fairness (recognition of characteristics of bargainers) in the choice of the appropriate contract. We show that the incremental cost contract, used to resolve the biodiversity bargaining problem, is of the form of an extreme point contract that fails to recognise the contributions of the South to the production of cooperative surplus. A rational response to such a contract is the use of threats of biodiversity destruction. Contracts must evince both efficiency and fairness in order to represent lasting solutions.     

Choquet Rationality

Consider a decision problem under uncertainty for a decision maker with known (utility) payoffs over prizes. We say that an act is Choquet (Shafer, Bernoulli) rational if for some capacity (belief function, probability) over the set of states, it maximizes her “expected” utility. We show that an act may be Choquet rational without being Bernoulli rational, but it is Choquet rational if and only if it is Shafer rational. Journal of Economic Literature Classification Numbers: C72, D81.     

Multilateral Bargaining Problems

In many situations in economics and political science there are gains from forming coalitions but conflict over which coalition to form and how to distribute the gains. This paper presents an approach to suchmultilateral bargaining problems. Asolutionto a multilateral bargaining problem specifies an agreement for each coalition that is consistent with the bargaining process in every coalition. We establish the existence of such solutions, show that they are determined by reservation prices, and characterize these reservation prices as the payoffs ofsubgame perfect equilibrium outcomesof a non-cooperative bargaining model.Journal of Economic LiteratureClassification Numbers: C71, C72, C78.     

The averaging mechanism

We consider two-person bargaining games and we assume that the agents want to apply two possibly different bargaining solutions. Problems arise if the allocations chosen by these bargaining solutions do not coincide. We propose a mechanism which mimics a step-by-step bargaining procedure in order to resolve such a conflict and give a characterization of the mechanism.     

Average Monotonic Cooperative Games

A subclass of monotonic transferable utility (T.U.) games is studied: average monotonic games. These games are totally balanced. We prove that the core coincides with both the bargaining set à la Davis and Maschler and the bargaining set à la Mas-Colell. To obtain this result a technique based on reduced games is used. Journal of Economic Literature Classification Number: C71     

Bargaining under Uncertainty and the Monotone Path Solutions

Uncertainty with respect to the feasible set of utility vectors is introduced in an axiomatic bargaining model. Given a criterion for nonprobabilistic decision-making under uncertainty, a natural efficiency requirement can be imposed on a bargaining solution. Using the maximin ordering, thestrictly monotone pathsolutions (generalizations of theegalitariansolution) to the bargaining problem are characterized as the only continuous solutions that satisfy this efficiency axiom. If the maximin criterion is replaced by the maximax ranking or a strict convex combination of the maximin and the maximax criterion, imposing our efficiency axiom and continuity leads to thedictatorialsolutions.Journal of Economic LiteratureClassification Number: C78.     

Characterizations of bargaining solutions in production economies with unequal skills

In production economies with unequal skills, this paper characterizes bargaining solutions by using axioms on allocation rules rather than axioms on classical bargaining solutions. We introduce a new axiom, consistency w.r.t. technological innovations, so that the non-welfaristic characterizations of bargaining solutions in the production economies are provided. By the characterizations, we can classify the three bargaining solutions (the Nash, the Kalai-Smorodinsky, and the Egalitarian solutions) from the viewpoint of responsibility and compensation discussed by Dworkin.     

A class of solutions to bargaining problems

A reformation of Nash's axiom of Independence of Irrelevant Alternatives is proposed, generalizing an idea due to Roth. It involves the concept of a reference function g, whose purpose is to summarize the main features of the bargaining problem and so facilitate the evaluation of the relative bargaining positions of the players. It is with respect to g that the Independence condition is reformulated. In conjunction with the other axioms used by Nash, it is shown that if g satisfies certain natural properties, the bargaining problem admits of a unique solution. Several examples of reference functions are shown to satisfy these conditions. An existence problem discovered by Roth for a particular choice of g is shown to be resolved if solutions are permitted to be multi-valued, the axioms being correspondingly reformulated.     

The dynamics of distributive politics

We study dynamic committee bargaining over an infinite horizon with discounting. In each period, a committee proposal is generated by a random recognition rule, the committee chooses between the proposal and a status quo by majority rule, and the voting outcome in period t becomes the status quo in period t + 1. We study symmetric Markov equilibria of the resulting game and conduct an experiment to test hypotheses generated by the theory for pure distributional (divide-the-dollar) environments. In particular, we investigate the effects of concavity in the utility functions, the existence of a Condorcet winning alternative, and the discount factor (committee “impatience”). We report several new findings. Voting behavior is selfish and myopic. Status quo outcomes have great inertia. There are strong treatment effects that are in the direction predicted by the Markov equilibrium. We find significant evidence of concave utility functions.     

Tiebout equilibria in local public good economies with spillovers

This paper analyzes the effects of spillovers on the equilibrium population distribution across jurisdictions in a local public good economy with free mobility. Spillovers are parametrized by a matrix [α_ij] where α_ij ∈ [0, 1]. When spillovers are symmetric and close to 0 or 1 (pure local public goods and pure public goods), all equilibrium jurisdiction structures are symmetric. However, any population distribution can be sustained in equilibrium for some value of the spillover parameter α. In the class of utility functions with additive externalities, we identify the unique family of utility functions for which equilibria are symmetric except for an isolated value of α. This is a class of utility functions which are linear in the public good and a power function of the private good, u(c, γ) = − A(1 − c)^β + γ. With this specification of utility, we show that an increase in α results in a more fragmented equilibrium population distribution, and that when spillovers are asymmetric and large, a jurisdiction which is more centrally located (i.e. benefits more from the public goods provided in other jurisdictions) has a larger population in equilibrium.     

On a probabilistic model of forecasting

One of the methods of studying complex objects is the construction of a mathematical model, containing such information about the object that is necessary to solve a definite problem connected with it.Mathematical modeling, based on the construction of models of various kinds can be used in forecasting. Let a forecasting object A(X) be described by vector X = (X₁, X₂,…,X_n) whose coordinates are parameters characterizing this object. The work presents a probabilistic model of forecasting and gives the example of a forecast of the object described by a set two parameters.