On the Existence of Stable Roommate Matchings

This paper identifies a condition called “no odd rings” that is sufficient for the existence of stable roommate matchings in the weak preferences case. It shows that the process of allowing randomly chosen blocking pairs to match converges to a stable roommate matching with probability one as long as there are no odd rings. This random-paths-to-stability result generalizes that of Roth and Vande Vate (1990, Econometrica58, 1475–1480) and may not hold if there are odd rings. The “no odd rings” condition can also be used to prove a number of other sufficient conditions that are more economically interpretable. Journal of Economic Literature Classification Numbers: C78, D71.     

Undominated Nash Implementation with Collusion and Renegotiation

This article looks at implementation in economic environments when agents have perfect information about the state of the world, but cannot commit not to renegotiate bad outcomes or to collude against each other. If renegotiation satisfies a weak condition of disagreement point monotonicity, then any Pareto-efficient social choice function can be implemented if there are at least three agents who play undominated Nash equilibria. The mechanism does not use modulo or integer games, has no bad mixed strategy equilibria, and is “bounded.”Journal of Economic LiteratureClassification Number: D71.     

Imitation processes with small mutations

This note characterizes the impact of adding rare stochastic mutations to an “imitation dynamic,” meaning a process with the properties that absent strategies remain absent, and non-homogeneous states are transient. The resulting system will spend almost all of its time at the absorbing states of the no-mutation process. The work of Freidlin and Wentzell [Random Perturbations of Dynamical Systems, Springer, New York, 1984] and its extensions provide a general algorithm for calculating the limit distribution, but this algorithm can be complicated to apply. This note provides a simpler and more intuitive algorithm. Loosely speaking, in a process with K strategies, it is sufficient to find the invariant distribution of a K×K Markov matrix on the K homogeneous states, where the probability of a transit from “all play i” to “all play j” is the probability of a transition from the state “all agents but 1 play i, 1 plays j” to the state “all play j”.     

Influence and inefficiency in the internal capital market

I model inefficient resource allocations in M-form organizations due to influence activities by division managers that skew capital budgets in their favor. Corporate headquarters receives two types of signals about investment opportunities: private signals that can be distorted by managers, and public signals that are undistorted but noisy. Headquarters faces a tradeoff between the cost of attaining an accurate private signal and the value of the information the signal provides. In contrast to existing models of “socialism” in internal capital markets, I show that investment sensitivity to Tobin's Q is higher than first-best in firms where division managers hold equity (a result consistent with evidence presented in Scharfstein, 1998). When managers face high private costs from distorting information (equity holdings), headquarters may commit to investment contracts that place “too little” weight on private signals and “too much” weight on public signals (i.e. Q). This result has implications for managers in the design of capital budgeting processes and incentive compensation systems.     

“Constitutionalizing” the corporation

To become effective instruments in the attainment of a sustainable society, corporations should have their constitutional status settled. Thus far, mainly by Supreme Court decisions, corporations have an uncertain status. They are “persons” under the Constitution and have certain rights; but unlike natural persons, they do not have concomitant constitutional duties. Corporations should be viewed as “private” governments exercising substantial power in society. They are, however, considered to be associations of individuals rather than divisions of society. The need is to legitimate their governing power by “constitutionalizing” them. That can be done by corporations accepting, or having imposed upon them, two principal constitutional duties. First, means should be developed whereby corporate officers routinely take the general good into account. That duty could be implemented by making “social impact statements,” analogous to but broader than the familiar environmental impact statements, before making important corporate decisions. Secondly, as “sociological communities,” corporate officers wield considerable power over members of those communities. A bill of rights similar to the Constitution's Bill of Rights is recommended so as to make corporate power that is necessary for achievement of societal goals as tolerable and decent as possible. Acceptance of those duties would make corporations parts of, not separate from, the greater corporation called society. They would be private, profit-making entities with a definite public function. Preferably, the duties should be voluntarily accepted. Congress, however, has undoubted constitutional power to impose both, should it so desire.     

Fashion statement

We study bilateral matching under private information about agents' characteristics. Assortative matching is the only equilibrium outcome in the absence of private information. When an information friction is present, the matching process can be improved if a payoff-irrelevant variable which we term “fashion” is introduced. Informed agents choose to adopt fashion as a signaling device. If success in matching is observed, other agents can imitate the signal. Thus, for fashion to be useful, it must constantly change. If there are more than two types of agents, both “high” and “low” fashion are needed to facilitate assortative matching.     

Pre-auction offers in asymmetric first-price and second-price auctions

We consider first-price and second-price auctions with asymmetric buyers, and examine whether pre-auction offers to a subset of buyers are profitable. A single offer is never profitable prior to a second-price auction, but may be profitable prior to a first-price auction. However, a sequence of offers is profitable in either type of auction. In our model, suitably chosen pre-auction offers work because they move the assignment when bidder valuations are “near the top” closer to the optimal, revenue-maximizing assignment.     

Consistent representative democracy

We study axioms which define “representative democracy” in an environment in which agents vote over a finite set of alternatives. We focus on a property that states that whether votes are aggregated directly or indirectly makes no difference. We call this property representative consistency. Representative consistency formalizes the idea that a voting rule should be immune to gerrymandering. We characterize the class of rules satisfying unanimity, anonymity, and representative consistency. We call these rules “partial priority rules.” A partial priority rule can be interpreted as a rule in which each agent can “veto” certain alternatives. We investigate the implications of imposing other axioms to the list specified above. We also study the partial priority rules in the context of specific economic models.     

Sequential decisions with tests

We consider a principal-agent problem where the principal wishes to be endorsed by a sequence of agents, but cannot truthfully reveal type. In the standard “herding” model, the agents learn from each other's decisions, which can lead to cascades on a given decision when later agents' private information is swamped. We augment the standard model to allow the principal to subject herself to a test designed to provide public information about her type. She must decide how tough a test to attempt from a continuum of test types, which involves trading off the higher probability of passing an easier test against the greater impact from passing a tougher test. We find that the principal will always choose to be tested, and will prefer a tough test to a neutral or easy one.     

Is man doomed to progress?

This paper is dedicated to the empirical exploration of the welfare effect of expectations and progress per se. Using 10 waves of the Russian Longitudinal Monitoring Survey (RLMS), a panel household survey rich in subjective variables, the analysis suggests that for a given total stock of inter-temporal consumption, agents are more satisfied with an increasing time profile of consumption: they seem to have a strong “taste for improvement”. This contributes to qualify the “Easterlin paradox” that income growth does not make people happy.     

Share contracts and macroeconomic externalities

Weitzman's analysis of the share economy contrasts fixed-wage and fixed-share contracts; this paper notes that neither is an optimal labor contract, rendering the comparison suspect. Given this comparison, though, share contracts may be superior to wage contracts in an economy characterized by a “macroeconomic externality,” whereby firm-level employment decisions affect the demand for other firms' goods.     

Eliciting Preferences to Assign Positions and Compensation

We describe strategy-proof rules for economies where an agent is assigned a position (e.g., a job) plus some of a divisible good. For the 2-agent–2-position case we derive a robust characterization. For the multi-agent–position case, many “arbitrary” such rules exist, so we consider additional requirements. By also requiring coalitional strategy-proofness or nonbossiness, the range of a solution is restricted to the point that such rules are not more complex than those for the Shapley–Scarf housing model (no divisible good). Third, we show that essentially only constant solutions are immune to manipulations involving “bribes.” Finally, we demonstrate a conflict between efficiency and strategy-proofness. The results extend to models (without externalities) in which agents share positions. Journal of Economic Literature Classification Numbers: C72, D70.     

Can Japan succeed in “Chigyo-ka” (intelprise-formation)?

There are two aspects in today's information revolution that started in the late 1970s. The first is an aspect referred to as “the third industrial revolution,” which triggers the transition to the “21st century system of Industrialization.” The information revolution in this sense brings the creation of new “breakthrough industries (new multimedia industries).” And the second aspect of the information revolution possesses the characteristics of both a technological revolution and a social revolution and brings about the arrival of the third phase of the historical evolutionary process of the modern civilization, which proceeds through three phases, namely “militarization, industrialization, and then informatization.”If the bearers of modern industrialization are a “group of enterprises” that have been engaged in the race in order to gain “wealth” (generalized means of exchange/exploitation power), and if these enterprises' activities have been exercised in the world market where their products have been sold, then it is appropriate to call the bearers of informatization a “group of intelprises.” They will be engaged in the race to gain “wisdom” (generalized means of persuasion/induction power), then stages of their activities can be called a “global intelplace” where “sharables,” that is, information and knowledge, will be disseminated. And now, toward the 21st century, the third phase of modernization, which can be called the “informatization/intelprise formation” or the “wisdom game” (intellectualism), is about to begin.Japan's “ie society (a society based on the ie principle—literally, it means “house” but here it is interpreted as cultural principle for organizing a society), which has been going through the process of evolution on the Japan Archipelago, has developed a network-based organization with little stratification within its infrastructure. In this sense, Japanese society can be characterized as a “network-oriented society” in which intelprises and an intelplace in the broad sense have functioned as the essential components of the society since Middle Ages. In general, an intelplace and intelprises that operate actively within this framework serve as the flexible bases for different types of social relations and institutions, such as states and markets and eventually integrate these into the society to a certain extent. In fact, it took place quite regularly during the modernization “in the narrow sense,” or Westernization of Japanese society after the Meiji Restoration. There exist some problems, however. Some of the characteristics found in Japanese society may become obstacles to activities aimed at the sharing and promotion of information and knowledge in the global intelplace and Japanese participation in the “wisdom game.” Badly needed are serious efforts for Japanese intelprise-formation to reduce these obstacles as much as possible.     

Rational Choice and the Condorcet Jury Theorem

In a recent paper, Austen-Smith and Banks (1996,Amer. Polit. Sci. Rev.90, 34–45), criticize the current literature on the Condorcet jury theorem as neglecting the behavioral underpinnings of decision-making. They leave open the question whether allowing mixed strategies would sustain the conclusions of the Condorcet jury theorem. In this paper, it is shown that these conclusions can hold in equilibrium. In other words, “a rational choice foundation for the claim that majorities invariably ‘do better’ than individuals” is derived. (Journal of Economic LiteratureClassification Number: D72.     

Anonymous yes–no voting with abstention and multiple levels of approval

Symmetric (3,2) simple games serve as models for anonymous voting systems in which each voter may vote “yes,” abstain, or vote “no,” the outcome is “yes” or “no,” and all voters play interchangeable roles. The extension to symmetric (j,2) simple games, in which each voter chooses from among j ordered levels of approval, also models some natural decision rules, such as pass–fail grading systems. Each such game is determined by the set of (anonymous) minimal winning profiles. This makes it possible to count the possible systems, and the counts suggest some interesting patterns. In the (3,2) case, the approach yields a version of May's Theorem, classifying all possible anonymous voting rules with abstention in terms of quota functions. In contrast to the situation for ordinary simple games these results reveal that the class of simple games with 3 or more levels of approval remains large and varied, even after the imposition of symmetry.     

Unfolding Social Hierarchies

Consider a large population of finitely-lived agents organized into n different hierarchical levels. Every period, all those placed at each level are randomly matched to play a given symmetric game. Based on the resulting outcome, a ρ-fraction of agents who (within their own level) attain the highest payoffs are promoted upwards. On the other hand, newcomers replacing those who die every period enter at the lowest level and choose irreversibly the strategy to be played for the rest of their life. This choice is made, with some noise, by imitating one of the strategies adopted at the highest level.  In this setup, the unique long-run behavior of the system is fully characterized for the whole class of 2×2 coordination games and two alternative variations of the model. The results crucially depend on the key “institutional” parameters ρ and n. In particular, it is shown that inefficient behavior prevails in the long run (even when risk-dominated) if promotion is only mildly selective—high ρ—and the social system is quite hierarchical—large n. In a stylized manner, these parameter conditions may be viewed as reflecting a sort of institutional deficiency that impairs economic performance. Journal of Economic Literature Classification Numbers: C70, C72, C73, D72.     

Optimality and Robustness of the English Auction

In Milgrom and Weber's (1982, Econometrica50, 1089–1122) “general symmetric model,” under a few additional regularity conditions, the English auction maximizes the seller's expected profit within the class of all posterior-implementable trading procedures and fails to do so among all interim incentive-compatible procedures in which “losers do not pay.” These results suggest that appropriate notions of robustness and simplicity which imply the optimality of the English auction for a risk-neutral seller must impose “bargaining-like” features on the set of feasible trading mechanisms. Journal of Economic Literature Classification Numbers: D44, D82.     

On optimality in collective institutional choice

Conditions are investigated under which democratic choice of the division of land between collective and “private” use and of the distribution of collective income between “needs” and “work” payments will produce a Pareto-optimal land allocation and optimal collective labor incentives. Sen's optimal rule for the degree of “needs” distribution is found to result from self-interested voting on this parameter when the distribution of labor inputs is unskewed or when votes are weighted by labor contributions. This in turn increases the optimality of land allocation, which can be further improved by a simple rental scheme. J. Comp. Econ., Dec. 1981, 5(4), pp. 392–403. Brown University, Providence, Rhode Island.     

Concatenate coordination and mutual coordination

We tell of the evolving meaning of the term coordination as used by economists. The paper is based on systematic electronic searches (on “coord,” etc.) of major works and leading journals. The term coordination first emerged in professional economics around 1880, to describe the directed productive concatenation of factors or activities within a firm. Also, transportation economists used the term to describe the concatenation of routes and trips of a transportation system. These usages represent what we term concatenate coordination. The next major development came in the 1930s from several LSE economists (Hayek, Plant, Hutt, and Coase), who extended that concept beyond the eye of any actual coordinator. That is, they wrote of the concatenate coordination of a system of polycentric or spontaneous activities. These various applications of concatenate coordination prevailed until the next major development, namely, Thomas Schelling and game models. Here coordination referred to a mutual meshing of actions. Game theorists developed crisp ideas of coordination games (like “battle of the sexes”), coordination equilibria, convention, and path dependence. This “coordination” was not a refashioning, but rather a distinct concept, one we distinguish as mutual coordination. As game models became more familiar to economists, it was mutual coordination that economists increasingly had in mind when they spoke of “coordination.” Economists switched, so to speak, to a new semantic equilibrium. Now, mutual coordination overshadows the older notion of concatenate coordination. The two senses of coordination are conceptually distinct and correspond neatly to the two dictionary definitions of the verb to coordinate. Both are crucial to economics. We suggest that distinguishing between the two senses can help to clarify “coordination” talk. Also, compared to talk of “efficiency” and “optimality,” concatenate coordination allows for a richer, more humanistic, and more openly aesthetic discussion of social affairs. The narrative is backed up by Excel worksheets that report on systematic content searches of the writings of economics using the worldwide web and, using JSTOR, of Quarterly Journal of Economics, Economic Journal, Journal of Political Economy, American Economic Review, and Economica.     

Topological games at Princeton, a mathematical memoir

The games of the title are “Nash” (or Hex), “Milnor” (or Y), “Shapley” (or Projective Plane) and “Gale” (or Bridg-It) all of which were discovered (or re-discovered) in Princeton in 1948–1949. After giving the basic topological connections, I will discuss more recent ramifications related to computational complexity theory. A recurrent theme will be non-constructive proofs, or how we can know something can be done without having the slightest idea of how to do it.