The Difference Indifference Makes in Strategy-Proof Allocation of Objects

We study the problem of allocating objects among people. We consider cases where each object is initially owned by someone, no object is initially owned by anyone, and combinations of the two. The problems we look at are those where each person has a need for exactly one object and initially owns at most one object (also known as house allocation with existing tenants"). We split with most of the existing literature on this topic by dropping the assumption that people can always strictly rank the objects. We show that, without this assumption, problems in which either some or all of the objects are not initially owned are equivalent to problems where each object is initially owned by someone. Thus, it suffices to study problems of the latter type.We ask if there are efficient rules that provide incentives for each person not only to participate (rather than stay home with what he owns), but also to state his preferences honestly. Our main contribution is to show that the answer is positive. The intuitive "top trading cycles" algorithm provides the only such rule for environments where people are never indifferent (Ma 1994). We generalize this algorithm in a way that allows for indifference without compromising on efficiency and incentives."strategy-proofness, indivisible goods, indifference, housing market, house allocation, kidney exchange

Dynamics of the Presidential Veto: A Computational

We specify and compute equilibria of a dynamic policy-making game between a president and a legislature under insitutional rules that emulate those of the US Constitution. Policies are assumed to lie in a two-dimensional space in which one issue dimension captures systemic differences in partisan preferences, while the other summarizes non-partisan attributes of policy. In any period, the policy choices of politicians are influenced by the position of the status quo policy in this space, with the current policy outcome determining the location of the status quo in the next period. Partisan control of the legislature and presidency changes probabilistically over time. We find that politicians strategically compromise their ideal policy in equilibrium, and that the degree of compromise increases when the opposition party is more likely to take control of the legislature in the next period, while politicians become relatively more extreme when the opposition party is more likely to control the presidency. We measure gridlock by (the inverse of ) the expected distance of enacted policies from the status quo in the long run, and we show that both gridlock and the long run welfare of a representative voter are maximized when government is divided without a super majority in the legislature. Under unified government, we find that the endogeneity of the status quo leads to a non-monotonic effect of the size of the legislative ma jority on gridlock; surprisingly, under unified government, gridlock is higher when the party in control of the legislature has a superma jority than when it has a bare ma jority. Furthermore, a relatively larger component of policy change occurs in the non-partisan policy dimension when a superma jority controls the legislature. We conduct constitutional experiments, and we find that voter welfare is minimized when the veto override provision is abolished and maximized when the presidential veto is abolished.

Lexicographic Composition of Choice Functions

Lexicographic composition is a natural way to build an aggregate choice function from component choice functions. As the name suggests, the components are ordered and choose sequentially. The sets that subsequent components select from are constrained by the choices made by earlier choice functions. The specific constraints affect whether properties like path independence are preserved. For several domains of inputs, we characterize the constraints that ensure such preservation

Learning matters: reappraising object allocation rules when agents strategically investigate

Individuals form preferences through search, interviews, discussion, and investigation. In a stylized object allocation model, we characterize the equilibrium learning strategies induced by different allocation rules and trace their welfare consequences. Our analysis reveals that top trading cycles rules dominate serial priority rules under inequality‐averse measures of social welfare

A network approach to public goods

Abstract We study settings where each agent can exert costly effort that creates nonrival, heterogeneous benefits for some of the others. For example, municipalities can forgo consumption to reduce pollution. How do the prospects for efficient cooperation depend on asymmetries in the effects of players' actions? We approach this question by analyzing a network that describes the marginal benefits agents can confer on one another. The first set of results explains how the largest eigenvalue of this network measures the marginal gains available from cooperating; as an application, we describe the players whose participation is essential to achieving any Pareto improvement on an inefficient status quo. Next, we examine mechanisms all of whose equilibria are Pareto efficient and individually rational; an outcome is called robust if it is an equilibrium outcome in every such mechanism. Robust outcomes exist and correspond to the Lindahl public goods solutions. The main result is a characterization of effort levels at these outcomes in terms of players' centralities in the benefits network. It entails that an outcome is robust if and only if agents contribute in proportion to how much they value the efforts of those who help them

Strategy-proof exchange under trichotomous preferences

We study the balanced exchange of indivisible objects without monetary transfers when agents may be endowed with (and consume) more than one object. We propose a natural domain of preferences that we call trichotomous. In this domain, each agent's preference over bundles of objects is responsive to an ordering over objects that has the following three indifference classes, in decreasing order of preferences: desirable objects, objects that she is endowed with but does not consider desirable, and objects that she neither is endowed with nor finds desirable. For this domain, we define a class of individually rational, Pareto-efficient, and strategy-proof mechanisms that are also computationally efficient. (C) 2021 Elsevier Inc. All rights reserved

Strategic and normative analysis of resource allocation problems.

Thesis (Ph. D.)--University of Rochester. Dept. of Economics, 2011.Economics is the study of how people use resources. The subject of this volume is then the study of economic problems. When resources are scarce, there are limits to the ways in which they can be used. In such an environment, people must choose a good way to allocate resources. Defining what we mean by "good" depends on the economic context and itself can be a challenging exercise. Once we know what makes a solution to an allocation problem a good one, the next task is to check that there is a good solution. If there is, a natural question is to ask "what are all of the good solutions?" This is the line of analysis that we apply to several economic situations. In the first chapter, we study the problem of choosing a point in a one-dimensional set over which people have single-dipped preferences. This applies to situations such as dividing a budget between two alternative public goods, locating a "public bad," and so on. The primary requirement that we examine is that an allocation rule be "strategy-proof." That is, it ought to be immune to strategic manipulations. We characterize the class of strategy-proof rules. In the second chapter, we consider the public choice between two alternatives when people may be indifferent between them. We analyze the implications of strategy-proofness and a more demanding version of strategy-proofness that deals with manipulations by groups. We identify the classes of all rules that satisfy each of these properties. In the third chapter, we look at the problem of rationing a divisible good among a group of people. Each person's preferences are characterized by an ideal amount that he would prefer to receive and a minimum quantity that he will accept: he finds any amount less than this threshold to be just as good as receiving nothing at all. Further, any amount beyond his ideal quantity has no effect on his welfare. We are interested in strategic properties, efficiency, and equity. We find these three requirements to be incompatible and identify the classes of all rules that satisfy each pair of them. The fourth and fifth chapters differ in structure from the earlier chapters. We analyze a novel model of "fractional matching." In the fourth chapter we define several normatively appealing properties of allocations and sort out their logical relations. In the fifth and final chapter, we take a new approach to matching and frame fractional matching problems in a general equilibrium context. This allows us to define a market-based solution to that has several desirable properties

Microstructure control and wear of Al2O3-SiC-(Al,Si) composites made by melt oxidation

Ceramic matrix composites of Al2O3-SiC-(Al,Si) have been fabricated by directed melt oxidation of aluminum alloys into SiC particulate preforms. The proportions of Al2O3, alloy, and porosity in the composite can be controlled by proper selection of SLC particle size and the processing temperature. The wear resistance of composites was evaluated in pin-on-disk experiments against a hard steel substrate. Minimum wear rate comparable to conventional ceramics such as ZTA is recorded for the composition containing the highest fraction of alloy, owing to the development of a thin and adherent tribofilm with a low coefficient of friction