9PM GMT (4PM Blacksburg, 6PM Rio de Janeiro, 9PM London, 10PM Paris, 12AM Istanbul, 6AM Wednesday in Tokyo/Seoul, 10AM Wednesday in Auckland)
Eric Bahel (Virginia Tech and National Science Foundation) "Anonymous and Strategy-Proof Voting under Subjective Expected Utility Preferences"
Host: Marcus Pivato
Abstract. We study three axioms in the model of constrained social choice under uncertainty where (i) agents have subjective expected utility preferences over acts and (ii) different states of nature have (possibly) different sets of available outcomes. Anonymity says that agents' names or labels should never play a role in the mechanism used to select the social act. Strategy-proofness requires that reporting one's true preferences be a (weakly) dominant strategy for each agent in the associated direct revelation game. Range unanimity essentially says that a feasible act must be selected by society whenever it is reported as every voter's favorite act within the range of the mechanism. We first show that every social choice function satisfying these three axioms can be factored as a product of voting rules that are either constant or binary (always yielding one of two pre-specified outcomes in each state). We describe four basic types of binary factors: three of these types are novel to this literature and exploit the voters' subjective beliefs. Our characterization result then states that a social choice function is anonymous, strategy-proof and range-unanimous if and only if every binary factor (in its canonical factorization) is of one of these four basic types.
2PM GMT (9AM New York, 11AM Rio de Janeiro, 2PM London, 3PM Munich, 5PM Istanbul, 7:30PM New Delhi, 11PM Tokyo/Seoul)
Felix Brandt (Technische Universität München) "Coordinating Charitable Donations"
Host: Marcus Pivato
Abstract. Charity is typically carried out by individual donors, who donate money to charities they support, or by centralized organizations such as governments or municipalities, which collect individual contributions and distribute them among a set of charities. Individual charity respects the will of the donors, but may be inefficient due to a lack of coordination; centralized charity is potentially more efficient, but may ignore the will of individual donors. We present a mechanism that combines the advantages of both methods for donors with Leontief preferences (i.e., each donor seeks to maximize an individually weighted minimum of all contributions across the charities). The mechanism distributes the contribution of each donor efficiently such that no subset of donors has an incentive to redistribute their donations. Moreover, it is group-strategyproof, satisfies desirable monotonicity properties, maximizes Nash welfare, can be computed efficiently via convex programming, and can be attained by natural best-response spending dynamics.
(Joint work with Matthias Greger, Erel Segal-Halevi, and Warut Suksompong.)
2PM GMT (9AM New York, 11AM Rio de Janeiro, 2PM Oxford, 3PM Paris, 5PM Istanbul, 7:30PM New Delhi, 11PM Tokyo/Seoul)
Teruji Thomas (Global Priorities Institute, University of Oxford) "The Multiverse and the Veil"
Host: Marcus Pivato
Abstract. I'll present a framework and some simple axioms that turn out to tightly constrain social choice under risk. Effectively, any social choice function is determined by its restriction to risk-free cases. For example, total welfare maximization in risk-free cases implies expected total welfare maximization in risky cases. Similarly, any social choice function is determined by its restriction to cases that involve only one person. Metaphorically speaking, social choice under risk is reduced to choice between risk-free "multiverses", or to choice for the sake of one person behind a "veil of ignorance". I will illustrate how this plays out with respect to various debates in population ethics and distributive ethics. In certain ways the axioms are very weak; for example, in working with choice functions, there's no assumption of expansion or contraction consistency, nor of other typical axioms of expected utility theory.
9PM GMT (4PM Kitchener-Waterloo, 6PM Rio de Janeiro, 9PM London, 10PM Paris, 12AM Istanbul, 6AM Wednesday in Tokyo/Seoul, 10AM Wednesday in Auckland)
Marc Kilgour (Wilfrid Laurier University) "Two-person fair allocation of indivisible items"
Host: Jobst Heitzig
Abstract. Whether independent agents can share a resource fairly, and how to do it, is an important and easily understood social choice problem. Among the criteria that have been proposed for a good allocation are maximum total utility, identified with utilitarianism, and maximum Nash utility, the basis of Nash bargaining. The Rawlsian idea of maximizing the minimum utility of any agent is also applicable. Yet another criterion is envy-freeness: one agent envies another if it prefers the other’s assignment to its own; in an envy-free allocation, no agent envies any other.
This presentation assumes a finite set of indivisible items, over which each of two players has known preferences. Preference is measured on a cardinal scale and is additive in that each player’s utility for any bundle of items is the sum of its utilities for the specific items in the bundle.
It is known that an envy-free allocation exists if and only if some maximin allocation gives each player at least half of the total utility in its own measure. Moreover, when this condition fails – so that no envy-free allocation exists – there is always an allocation with the related property called EFx. The focus here is on the existence of envy-freeness and its relation to efficiency-related properties such as maximum utility sum and maximum Nash product. After a formal study of what is possible, a comprehensive simulation is conducted to measure the frequencies of the various possibilities.
The objective of this study is to identify properties of allocation problems that can potentially simplify the task of fair allocation, demonstrate their existence and relationships, and assess how difficult they are to use in simulations.
(Joint work with Rudolf Vetschera, Steven Brams, Christian Klamler, and Fan Wei.)
2PM GMT (9AM Boston, 11AM Rio de Janeiro, 2PM London, 3PM Paris, 5PM Istanbul, 7:30PM New Delhi, 11PM Tokyo/Seoul)
Arpita Biswas (Harvard University) "Fair Allocation of a Conflict Graph"
Host: Marcus Pivato
Abstract. The problem of fair allocation of indivisible items becomes more complicated when certain item pairs conflict with each other, rendering those pairs incompatible while allocating them to the same agent. This problem setting finds its relevance in scenarios such as course allocation, where students (the agents) express preferences for courses (the items), and courses may possess conflicting schedules which is represented by an interval conflict graph. Additionally, courses have finite seat capacities, and students may have constraints on the number of courses they can enroll in. The goal is to obtain a fair and feasible allocation of items among the agents while ensuring that each allocated bundle constitutes an independent set within the interval conflict graph. While the problem is NP-hard for a general conflict graph, we devise efficient solutions when items are represented as intervals, that is, considering an interval conflict graph. In this talk, I’ll discuss various fairness notions, such as maximin fairness and almost envy freeness, that are pertinent to this problem setting and present solutions using a number of interesting techniques that are tailored to different assumptions on the agents’ preferences over a bundle of items — uniform additive, binary additive, identical additive, and non-identical (general) additive preferences.
2PM GMT (10AM New York, 11AM Rio de Janeiro, 2PM London, 3PM Paris, 5PM Istanbul, 7:30PM New Delhi, 11PM Seoul/Tokyo)
Brian Hill (CNRS and HEC Paris) "Confidence, consensus and aggregation"
Host: Marcus Pivato
Abstract. This paper develops and defends a new approach to belief aggregation, involving confidence in beliefs. It is characterised by a variant of the Pareto condition that enjoins respecting consensuses borne of compromise. Confidence aggregation recoups standard probability aggregation rules, such as linear pooling, as special cases, whilst avoiding the spurious unanimity issues that have plagued such rules. Moreover, it generates a new family of probability aggregation rules that can faithfully accommodate within-person expertise diversity, hence resolving a longstanding challenge. Confidence aggregation also outperforms linear aggregation: the group beliefs it provides are closer to the truth, in expectation. Finally, confidence aggregation is dynamically rational: it commutes with update.
9AM GMT (5AM New York, 6AM Rio de Janeiro, 10AM London, 11AM Paris, 12PM Istanbul, 1PM Abu Dhabi, 2:30PM New Delhi, 6PM Seoul/Tokyo, 10PM Auckland)
Yuki Tamura (NYU Abu Dhabi) "Obviously strategy-proof rules for object reallocation"
Host: Simona Fabrizi
Abstract. For object reallocation problems, Bade (2019) defines a rule, the ''crawler'', and shows that on the domain of single-peaked preferences, this rule satisfies efficiency, the endowments lower bounds, and obvious strategy-proofness. Her result raises the question of whether other rules exist that satisfy these properties. We provide a complete answer to this question. Based on the idea underlying the crawler, we obtain a family of rules that we call ''crawler-jumper rules". We show that a rule satisfies efficiency, the endowments lower bounds, and obvious strategy-proofness if and only if it is a crawler-jumper rule.
2PM GMT (10AM Boston, 11AM Rio de Janeiro, 3PM Warwick, 4PM Paris, 5PM Istanbul, 7:30PM New Delhi, 11PM Tokyo/Seoul)
Markus Brill (University of Warwick) "Robust and Verifiable Proportionality Axioms for Multiwinner Voting"
Host: Marcus Pivato
Abstract. When selecting a subset of candidates (a so-called committee) based on the preferences of voters, proportional representation is often a major desideratum. When going beyond simplistic models such as party-list or district-based elections, it is surprisingly challenging to capture proportionality formally. As a consequence, the literature has produced numerous competing criteria of when a selected committee qualifies as proportional. Two of the most prominent notions are Dummett's proportionality for solid coalitions (PSC) and Aziz et al.'s extended justified representation (EJR). Both definitions guarantee proportional representation to groups of voters who have very similar preferences; such groups are referred to as solid coalitions by Dummett and as cohesive groups by Aziz et al. However, these notions lose their bite when groups are only almost solid or almost cohesive. In this paper, we propose proportionality axioms that are more robust than their existing counterparts, in the sense that they guarantee representation also to groups that do not qualify as solid or cohesive. Importantly, we show that these stronger proportionality requirements are always satisfiable. Another important advantage of our novel axioms is that their satisfaction can be easily verified: Given a committee, we can check in polynomial time whether it satisfies the axiom or not. This is in contrast to many established notions like EJR, for which the corresponding verification problem is known to be intractable.
In the setting with approval preferences, we propose a robust and verifiable variant of EJR and a simple greedy procedure to compute committees satisfying it. We show that our axiom is considerably more discriminating in randomly generated instances compared to EJR and other existing axioms. In the setting with ranked preferences, we propose a robust variant of Dummett's PSC. In contrast to earlier strengthenings of PSC, our axiom can be efficiently verified even for general weak preferences. In the special case of strict preferences, our notion is the first known satisfiable proportionality axiom that is violated by the Single Tranferable Vote (STV). In order to prove that our axiom can always be satisfied, we extend the notion of priceability to the ranked preferences setting. We also discuss implications of our results for participatory budgeting, querying procedures, and to the notion of proportionality degree.
Joint work with Jannik Peters (TU Berlin).
2PM GMT (10AM Boston, 11AM Rio de Janeiro, 3PM London, 4PM Paris, 5PM Istanbul, 7:30PM New Delhi, 11PM Tokyo/Seoul)
Evi Micha (Harvard University) "Fair and Representative Citizens' Assemblies"
Host: Marcus Pivato
Abstract. Sortition is based on the idea of choosing randomly selected representatives for decision-making. The main properties that make sortition particularly appealing are fairness — all citizens can be selected with the same probability — and proportional representation — a randomly selected panel likely reflects the composition of the whole population. When a population lies on a representation metric, we formally define proportional representation using a notion called the core. A panel is in the core if no group of individuals is underrepresented proportional to its size. While uniform selection is fair, it does not always return panels that are in the core. Thus, we ask: Can we design a selection algorithm that satisfies fairness and the core simultaneously? We answer this question affirmatively and present an efficient selection algorithm, called Fair Greedy Capture, that is fair and provides a constant-factor approximation to the optimal core. We also ask: Do these panels reflect the entire population’s opinion? We present a positive answer by adopting the concept of metric distortion. We show that while uniform selection does not provide a reasonable distortion, Fair Greedy Capture achieves a constant distortion.
2PM GMT (10AM New York, 11AM Rio de Janeiro, 3PM London, 4PM Paris, 5PM Istanbul, 7:30PM New Delhi, 11PM Tokyo/Seoul)
Double Feature
Pierre Bardier (Paris School of Economics) "The probability to satisfy axioms: a non-binary perspective on economic design, voting and social choice"
and
Rajarshi Ghosh (ESSEC and CY Cergy Paris Université) "Quadratically Normalized Utilitarian Voting"
Host: Danilo Coelho
Abstract. (Pierre Bardier) In the theory of economic design and voting, incompatibilities between axioms have given rise to a myriad of notions of the degree to which a given axiom is satisfied. However, these are, generally, model-and-axiom-specific. In contrast, this paper explores the potential of defining such a notion as the probability with which an axiom, as well as a set of axioms, is satisfied, without restricting the analysis to particular types of properties or problems.
The formal framework we provide is consistent with the use of simulation models, which aim at assessing the empirical performance of rules but focus, in general, on a single axiom, of a particular type.
We then propose and axiomatize a criterion to evaluate and compare the performance of rules given a set of axioms, based on two key components: the probabilities of satisfaction and the normative desirability of axioms, and, crucially, that of their combinations. Finally, we propose and axiomatize a criterion to measure axioms' compatibility between each other for a given rule, building on an analogy with cooperative game theory.
Abstract. (Rajarshi Ghosh) We propose a new voting mechanism in which voters simultaneously report their von Neumann-Morgenstern (vNM) utility functions across multiple decision problems, each of which has a finite number of alternatives. Each voter must report a real-valued “valuation” for each alternative of each decision. Each voter’s valuation vector is rescaled to have unit magnitude (where this magnitude is measured using a specially constructed quadratic form). We show that it is a dominant strategy for each voter to reveal her true vNM utility function. With very high probability, the mechanism selects the alternative that maximizes a weighted utilitarian social welfare function. The mechanism does not use money, and does not assume quasilinear utilities.
(Joint work with Marcus Pivato)
2PM GMT (10AM New York, 11AM Rio de Janeiro, 3PM London, 4PM Paris, 5PM Istanbul, 7:30PM New Delhi, 11PM Tokyo/Seoul)
Søren Riis (Queen Mary University of London) "AI Meets Condorcet Domains in Social Choice"
Host: Jobst Heitzig
Abstract. This talk explores recent advances in Condorcet Domains (CDs), aimed at both specialists and general researchers in the social choice community. We begin by reporting on a complete classification of all maximal CDs with up to 7 alternatives, now available in an online database. This work, a joint effort with Akello-Egwel, Leedham-Green, Litterick, and Markström, utilized extensive parallel computation with a specialized C++ program on a supercomputer at the University of Umeå, Sweden.
Next, we present insights into the optimal CD size of 224 for 8 alternatives, a joint finding with Leedham-Green and Markström.
We then discuss work on new families of CDs, highlighting AI-inspired reinforcement learning algorithms used in collaboration with Zhou. Our algorithm, incorporating domain-specific knowledge and special C++ libraries, significantly outperforms standard search algorithms including reinforcement learning algorithms, evolution computations, and local search algorithms.
Using this new algorithm, in a special parallelised version, combined with human mathematical intuition and domain-specific knowledge, we discovered new families of large CDs in collaboration with Markström, Karpov, and Zhou.
Finally, we report on ongoing research into constructing maximal-size CDs and potentially identifying all local maxima for larger CDs, in collaboration with Markström, Karpov, and Zhou.
This session offers an overview and invites further collaboration on related problems where AI techniques might be beneficial.
2PM GMT (10AM New York, 11AM Rio de Janeiro, 3PM London, 4PM Paris, 5PM Istanbul, 7:30PM New Delhi, 11PM Tokyo/Seoul)
Hadi Hosseini (Pennsylvania State University) "Two-Sided Strategies in Stable Matching Markets"
Host: Danilo Coelho
Abstract. The incompatibility between stability and strategyproofness in stable matching markets has given rise to a variety of “one-sided” manipulation studies where misreporting agents are also the intended beneficiaries. In this talk, I will introduce a novel “two-sided” manipulation framework wherein the misreporting agent(s) and the beneficiary may be on different sides of the market. In particular, I will describe two-sided manipulation strategies in the following variations: (i) accomplice manipulation, with a misreporting agent (say, an accomplice man) and a single beneficiary (say, a woman); (ii) one-for-all manipulation, with the misreporting agent (man) and multiple beneficiaries (all women); and (iii) two-for-one manipulation, with a pair of misreporting agents (man and woman) and a single beneficiary (the misreporting woman). I will discuss several structural results on optimal manipulation strategies, their consequences in designing manipulation algorithms, and the conditions under which the stability of the resulting matchings is preserved.
2PM GMT (10AM New York, 11AM Rio de Janeiro, 3PM London, 4PM Stockholm, 5PM Istanbul, 7:30PM New Delhi, 11PM Tokyo/Seoul)
H. Orri Stefánsson (Stockholm University and Swedish Collegium for Advanced Study) " In defence of Pigou-Dalton for chances"
Host: Marcus Pivato
Abstract. I defend a weak version of the Pigou–Dalton principle for chances. The principle says that it is better to increase the survival chance of a person who is more likely to die rather than a person who is less likely to die, assuming that the two people do not differ in any other morally relevant respect. The principle justifies plausible moral judgements that standard ex post views, such as prioritarianism and rank-dependent egalitarianism, cannot accommodate. However, the principle can be justified by the same reasoning that has recently been used to defend the core axiom of ex post prioritarianism and egalitarianism, namely, Pigou–Dalton for well-being. The arguably biggest challenge for proponents of Pigou–Dalton for chances is that it violates statewise dominance for social prospects. However, I argue that we have independent reason for rejecting statewise dominance for social prospects, since on a standard interpretation of the principle (in particular, an interpretation that is inconsistent with Pigou–Dalton for chances), it prevents a social planner from properly respecting people’s attitudes to risk.
2PM GMT (10AM Amherst, 11AM Rio de Janeiro, 3PM London, 4PM Paris, 5PM Istanbul, 7:30PM New Delhi, 11PM Tokyo/Seoul)
Yair Zick (University of Massachusetts, Amherst) "Fair and Efficient Allocation of Indivisible Items Under Submodular Valuations"
Host: Marcus Pivato
Abstract. In this talk I will describe some recent progress in computational fair division of indivisible items, when agents have submodular valuations. We will start with the setting where agents with matroid rank valuations -- every good provides a marginal value of 0 or 1 when added to a bundle and valuations are submodular. We will describe the Yankee Swap algorithm, a simple framework that can efficiently compute allocations that maximize any justice criterion (or fairness objective) satisfying some mild assumptions. Yankee Swap is guaranteed to maximize utilitarian social welfare, ensure strategyproofness and use at most a quadratic number of valuation queries. We will discuss how the framework can be generalized to settings where agents have bivalued submodular utilities, as well as settings with mixed manna. Finally, we will describe some recent hardness of approximation results when agents have more than two possible marginal gains.
Relevant papers:
Fitzsimmons, Viswanathan and Zick "On the Hardness of Fair Allocation Under Ternary Valuations", 2024, in preparation.
Viswanathan and Zick "A General Framework for Fair Allocation under Matroid Rank Valuations", EC 2023
Cousins, Viswanathan and Zick "Dividing Good and Great Items Among Agents with Bivalued Submodular Valuations", WINE 2023
Cousins, Viswanathan and Zick "The good, the bad and the submodular: Fairly allocating mixed manna under order-neutral submodular preferences", WINE 2023
2PM GMT (10AM Fairfax, 11AM Rio de Janeiro, 3PM London, 4PM Paris, 5PM Istanbul, 7:30PM New Delhi, 11PM Tokyo/Seoul)
César Martinelli (George Mason University) "Why Do People Protest? A Theory of Emotions, Public Policy, and Political Unrest"
Host: Marcus Pivato
Abstract. We build a model of policymaking under the threat of unrest. A policymaker chooses how much effort to spend on a public good; effort is unobservable and the outcome conditional on effort is uncertain. A group of citizens protest if the outcome falls short of a reference point; the reference point is determined endogenously by rational expectations about the outcome and by the height of emotions. We show that the effects of stronger emotional reactions on policymaker’s effort and the probability of protest are nonmonotonic and depend on the group’s ability to inflict damage. Equilibrium may require the policymaker to randomize between providing some effort or no effort at all, in order to temper citizens’ aspirations, in which case strong emotional reactions are counterproductive. Optimal emotional reactions are fine-tuned to minimize the probability of protest.
(Joint work with Ruolong Xiao.)
2PM GMT (10AM New York, 11AM Rio de Janeiro, 3PM London, 4PM Paris, 5PM Istanbul, 7:30PM New Delhi, 11PM Tokyo/Seoul)
Kohei Kamaga (Sophia University) "Ex-post approaches to prioritarianism and sufficientarianism"
Host: Marcus Pivato
Abstract. Although sufficientarianism has been gaining interest as a theory of distributive justice in recent years, it has not been examined in the presence of risk. We propose an ex-post approach to sufficientarianism that has a strong link to ex-post prioritarianism. Both ex-post criteria are based on an axiom that we refer to as prospect independence of the unconcerned, a natural extension of the independence axiom known from the literature that focuses on situations with no risk. We characterize a class of ex-post prioritarian orderings as well as the corresponding class of ex-post sufficientarian orderings. In addition, we point out some important differences between these two ex-post criteria, and we examine how they fare when assessed in terms of specific ex-ante Paretian axioms.
(joint work with Matthew D. Adler, Walter Bossert and Susumu Cato)
2PM GMT (10AM New York, 11AM Rio de Janeiro, 3PM London, 4PM Vienna, 5PM Istanbul, 7:30PM New Delhi, 11PM Tokyo/Seoul)
Jan Maly (Wirtshaftsuniversität Wien) "Committees and Equilibria: Multiwinner Approval Voting Through the Lens of Budgeting Games"
Host: Marcus Pivato
Abstract. Approval-based multiwinner voting, one of the central topics in computational social choice, addresses collective decision-making scenarios in which n voters select a committee of k candidates from a larger pool of alternatives. A fundamental aim is to ensure that the elected committee proportionately represents the preferences of the electorate. Consequently, much effort has gone into exploring various proportionality notions and developing voting rules to achieve them. A key intuition underlying many fairness axioms and voting rules is that an optimal outcome is attained when no subset of voters can improve their position by reallocating their endorsements. In this talk, I will formalize this intuition by defining a new class of games called budgeting games, where committees occur as a result of voters’ decisions about how to allocate a given budget. I will introduce this new class of normal-form games and show that key notions in multiwinner voting theory, such as priceability, the core and EJR (Extended Justified Representation) can be thought of as equilibria of budgeting games. In doing so, I will leverage the game-theoretic approach to provide a new perspective on one of the major open problems in multiwinner voting, namely non-emptiness of the core. Moreover, budgeting games do not just capture existing concepts, but also give rise to entirely new families of voting rules. These rules, which are guaranteed to satisfy desirable fairness axioms, are based on improving-move dynamics in the respective budgeting games, and include the well-known Method of Equal Shares.
2PM GMT (10AM New York, 11AM Rio de Janeiro, 3PM London, 4PM Paris, 5PM Istanbul, 7:30PM New Delhi, 10PM Singapore, 11PM Tokyo/Seoul)
Warut Suksompong (National University of Singapore) "Weighted Fair Division: Additive Preferences and Beyond"
Host: Danilo Coelho
Abstract. Fair resource allocation is a fundamental problem in society, with applications ranging from inheritance division to ministry allocation. While the fair division literature typically assumes that all agents have the same entitlement to the resource, several practical applications involve agents with varying entitlements represented by weights. I will present the highlights of my work on weighted fair division of indivisible resources, which include (i) adapting standard fairness notions such as envy-freeness and proportionality to the weighted setting; (ii) generalizing prominent allocation algorithms such as picking sequences and maximum Nash welfare to incorporate weights; and (iii) analyzing algorithms with respect to axiomatic properties including fairness, monotonicity, and strategyproofness. I will also discuss the progress and challenges of extending the results beyond additive preferences.
(Joint work with Mithun Chakraborty, Ayumi Igarashi, Luisa Montanari, Ulrike Schmidt-Kraepelin, Erel Segal-Halevi, Nicholas Teh, and Yair Zick)
2PM GMT (10AM Pittsburgh, 11AM Rio de Janeiro, 2PM London, 3PM Paris, 5PM Istanbul, 7:30PM New Delhi, 11PM Seoul/Tokyo)
Vincent Conitzer (Carnegie Mellon University) "Getting AI systems (collectively) to behave the way we (collectively) want them to"
Host: Marcus Pivato
Abstract. It is often hard to get an AI system to do what someone really wants it to do -- a problem referred to as "aligning" the AI. But even if we can solve that problem reasonably well, other problems remain. One is the problem of accounting for multiple stakeholders: we generally want to take into account the preferences, values, or judgments of more than one party, even if they conflict with each other. Another is the problem of multiple interacting AI systems: even if each of these systems individually is, on its own, reasonably well aligned, interactions among them can produce disastrous outcomes. I will give an overview of these problems, and will argue that we can address them using social choice theory and game theory.
Time: 2PM GMT (9AM New York, 11AM Rio de Janeiro, 2PM London, 3PM Zürich, 5PM Istanbul, 7:30PM New Delhi, 11PM Seoul/Tokyo) [North Americans please note time change]
Maya Eden (Universität Zürich) "The Irrelevance of Intergenerational Altruism for Social Discounting"
Host: Marcus Pivato
Abstract. Should people's concern for the wellbeing of their descendants affect policy decisions? I consider a model with intergenerational altruism in which the social welfare function is a sum of past, present and future dynastic utilities. I establish that, under plausible assumptions, intergenerational altruism has no effect on the social ranking, and can be ignored for the purpose of policy decisions. The reason is that each generation's concern for its children cancels out with their parents' concern for them.
2PM GMT (9AM New York, 11AM Rio de Janeiro, 2PM Oxford, 3PM Paris, 5PM Istanbul, 7:30PM New Delhi, 11PM Tokyo/Seoul)
Loren Fryxell (Global Priorities Institute, University of Oxford) "Public Good Provision Re-Examined"
Host: Marcus Pivato
Abstract. I write down the government's public good provision problem from first principles and find a unique solution, contrary to conventional wisdom. I call it the cost-sharing generalized pivotal mechanism. The cost-sharing generalized pivotal mechanism elicits individuals' private willingness to pay for the public good in dominant strategies, induces participation in dominant strategies, produces the welfare-maximizing quantity of the public good via a weighted benefit-cost analysis, finances exactly the cost of the public good, and taxes individuals fairly. Moreover, I show that the most well-known mechanism for public good provision, the Clarke mechanism, violates budget-balance, participation, fairness, and a basic principle I call no-extortion: if nothing is produced, no one should pay.