Proceedings of the fifteenth ACM conference on Economics and computation最新文献

{"title":"Strategyproof allocation of discrete jobs on multiple machines","authors":"E. Friedman, A. Ghodsi, Alexandros Psomas","doi":"10.1145/2600057.2602889","DOIUrl":"https://doi.org/10.1145/2600057.2602889","url":null,"abstract":"We present a model for fair strategyproof allocations in a realistic model of cloud computing centers. This model has the standard Leontief preferences but also captures a key property of virtualization, the use of containers to isolate jobs. We first present several impossibility results for deterministic mechanisms in this setting. We then construct an extension of the well known dominant resource fairness mechanism (DRF), which somewhat surprisingly does not involve the notion of a dominant resource. Our mechanism relies on the connection between the DRF mechanism and the Kalai-Smorodinsky bargaining solution; by computing a weighted max-min over the convex hull of the feasible region we can obtain an ex-ante fair, efficient and strategyproof randomized allocation. This randomized mechanism can be used to construct other mechanisms which do not rely on users' being expected (ex-ante) utility maximizers, in several ways. First, for the case of $m$ identical machines one can use the convex structure of the mechanism to get a simple mechanism which is approximately ex-post fair, efficient and strategyproof. Second, we present a more subtle construction for an arbitrary set of machines, using the Shapley-Folkman-Starr theorem to show the existence of an allocation which is approximately ex-post fair, efficient and strategyproof. This paper provides both a rigorous foundation for developing protocols that explicitly utilize the detailed structure of the modern cloud computing hardware and software, and a general method for extending the dominant resource fairness mechanism to more complex settings.","PeriodicalId":203155,"journal":{"name":"Proceedings of the fifteenth ACM conference on Economics and computation","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127195182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simple approximate equilibria in large games","authors":"Y. Babichenko, Siddharth Barman, R. Peretz","doi":"10.1145/2600057.2602873","DOIUrl":"https://doi.org/10.1145/2600057.2602873","url":null,"abstract":"We prove that in every normal form n-player game with m actions for each player, there exists an approximate Nash equilibrium in which each player randomizes uniformly among a set of O(log m + log n) pure actions. This result induces an O(N log log N)-time algorithm for computing an approximate Nash equilibrium in games where the number of actions is polynomial in the number of players (m=poly(n)); here N=nmn is the size of the game (the input size). Furthermore, when the number of actions is a fixed constant (m=O(1)) the same algorithm runs in O(Nlog log log N) time. In addition, we establish an inverse connection between the entropy of Nash equilibria in the game, and the time it takes to find such an approximate Nash equilibrium using the random sampling method. We also consider other relevant notions of equilibria. Specifically, we prove the existence of approximate correlated equilibrium of support size polylogarithmic in the number of players, n, and the number of actions per player, m. In particular, using the probabilistic method, we show that there exists a multiset of action profiles of polylogarithmic size such that the uniform distribution over this multiset forms an approximate correlated equilibrium. Along similar lines, we establish the existence of approximate coarse correlated equilibrium with logarithmic support. We complement these results by considering the computational complexity of determining small-support approximate equilibria. We show that random sampling can be used to efficiently determine an approximate coarse correlated equilibrium with logarithmic support. But, such a tight result does not hold for correlated equilibrium, i.e., sampling might generate an approximate correlated equilibrium of support size Ω(m) where m is the number of actions per player. Finally, we show that finding an exact correlated equilibrium with smallest possible support is NP-hard under Cook reductions, even in the case of two-player zero-sum games.","PeriodicalId":203155,"journal":{"name":"Proceedings of the fifteenth ACM conference on Economics and computation","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126820119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimal contest design for simple agents","authors":"Arpita Ghosh, Robert D. Kleinberg","doi":"10.1145/2600057.2602875","DOIUrl":"https://doi.org/10.1145/2600057.2602875","url":null,"abstract":"We study the optimal design of contests for 'simple' agents, where potential contestants strategically reason about whether or not to participate in the contest, but do not strategize about the quality of their submissions. Consider a population of n agents, where an agent with type (qi, ci chooses between participating and producing a submission of quality qi at cost ci, versus not participating at all, to maximize her utility. How should a principal distribute a total prize V amongst the n ranks to maximize some increasing function of the qualities of elicited submissions in a contest with such simple agents' We first solve the optimal contest design problem in settings where agents have homogenous participation costs ci = c. Here, the contest that maximizes every increasing function of the elicited contributions qi is always a simple contest, awarding equal prizes of V/j* each to the top j* = V/c - Θ (√V/(c ln (V/c))) contestants. This is in contrast with the optimal contest structure in comparable models with strategic effort choices, where the optimal contest is either a winner-take-all contest or awards possibly unequal prizes, depending on the curvature of agents' effort cost functions. We next address the general case with heterogenous costs ci: here, agents' types (qici are inherently two-dimensional, which significantly complicates equilibrium analysis. With heterogenous costs, the optimal contest depends on the objective being maximized; our main result here is that the winner-take-all contest is a 3-approximation of the optimal contest when the principal's objective is to maximize the quality of the best elicited contribution. The proof of this result hinges around a `sub-equilibrium' lemma, which establishes a stochastic dominance relation between the distribution of qualities elicited in an equilibrium and a sub-equilibrium---a strategy profile that is a best response for all agents who choose to participate in that strategy profile; this relation between equilibria and sub-equilibria may be of more general interest.","PeriodicalId":203155,"journal":{"name":"Proceedings of the fifteenth ACM conference on Economics and computation","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128593724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bounds for the query complexity of approximate equilibria","authors":"P. Goldberg, Aaron Roth","doi":"10.1145/2600057.2602845","DOIUrl":"https://doi.org/10.1145/2600057.2602845","url":null,"abstract":"We analyze the number of payoff queries needed to compute approximate equilibria of multi-player games. We find that query complexity is an effective tool for distinguishing the computational difficulty of alternative solution concepts, and we develop new techniques for upper- and lower bounding the query complexity. For binary-choice games, we show logarithmic upper and lower bounds on the query complexity of approximate correlated equilibrium. For well-supported approximate correlated equilibrium (a restriction where a player's behavior must always be approximately optimal, in the worst case over draws from the distribution) we show a linear lower bound, thus separating the query complexity of well supported approximate correlated equilibrium from the standard notion of approximate correlated equilibrium. Finally, we give a query-efficient reduction from the problem of computing an approximate well-supported Nash equilibrium to the problem of verifying a well supported Nash equilibrium, where the additional query overhead is proportional to the description length of the game. This gives a polynomial-query algorithm for computing well supported approximate Nash equilibria (and hence correlated equilibria) in concisely represented games. We identify a class of games (which includes congestion games) in which the reduction can be made not only query efficient, but also computationally efficient.","PeriodicalId":203155,"journal":{"name":"Proceedings of the fifteenth ACM conference on Economics and computation","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130848432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two-sided matching with one-sided preferences","authors":"Guillaume Haeringer, Vincent Iehlé","doi":"10.1145/2600057.2602853","DOIUrl":"https://doi.org/10.1145/2600057.2602853","url":null,"abstract":"In a school choice context we show that considering only schools' priorities and the set of acceptable schools for each student - but not how these schools are ranked in their preferences - we can restrict the set of possible stable matchings that can arise for any preference profile of the students that leaves the set of acceptable schools unchanged. We characterize impossible matches, i.e., of pairs student school that cannot be matched at any stable matching, for any preference profile. Our approach consists of linking Hall's marriage condition to stable matchings. Our results offer a new methodology to assess to what extent the preferences on one side of a matching market can preset the stable matchings that can emerge. First, we use this technique to discuss the impact of priority zoning in school choice problems. Second, a new mechanism for school choice problems is proposed. It is shown that it (weakly) Pareto dominates the Student Optimal Stable Mechanism and retain some of its incentives.","PeriodicalId":203155,"journal":{"name":"Proceedings of the fifteenth ACM conference on Economics and computation","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129657264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Why marketplace experimentation is harder than it seems: the role of test-control interference","authors":"Thomas Blake, Dominic Coey","doi":"10.1145/2600057.2602837","DOIUrl":"https://doi.org/10.1145/2600057.2602837","url":null,"abstract":"Classical statistical inference of experimental data assumes that the treatment affects the test group but not the control group. This assumption will typically be violated when experimenting in marketplaces because of general equilibrium effects: changing test demand affects the supply available to the control group. We illustrate this with an email marketing campaign performed by eBay. Ignoring test-control interference leads to estimates of the campaign's effectiveness which are too large by a factor of around two. We present the simple economics of this bias in a supply and demand framework, showing that the bias is larger in magnitude where there is more inelastic supply, and is positive if demand is elastic.","PeriodicalId":203155,"journal":{"name":"Proceedings of the fifteenth ACM conference on Economics and computation","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124981397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Approximate revenue maximization in interdependent value settings","authors":"Shuchi Chawla, Hu Fu, Anna R. Karlin","doi":"10.1145/2600057.2602858","DOIUrl":"https://doi.org/10.1145/2600057.2602858","url":null,"abstract":"We study revenue maximization in settings where agents' values are interdependent: each agent receives a signal drawn from a correlated distribution and agents' values are functions of all of the signals. We introduce a variant of the generalized VCG auction with reserve prices and random admission, and show that this auction gives a constant approximation to the optimal expected revenue in matroid environments. Our results do not require any assumptions on the signal distributions, however, they require the value functions to satisfy a standard single-crossing property and a concavity-type condition.","PeriodicalId":203155,"journal":{"name":"Proceedings of the fifteenth ACM conference on Economics and computation","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123376077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cournot competition in networked markets","authors":"K. Bimpikis, S. Ehsani, Rahmi Ilkiliç","doi":"10.1145/2600057.2602882","DOIUrl":"https://doi.org/10.1145/2600057.2602882","url":null,"abstract":"The paper considers a model of competition among firms that produce a homogeneous good in a networked environment. A bipartite graph determines which subset of markets a firm can supply to. Firms compete a la Cournot and decide how to allocate their production output to the markets they are directly connected to. We assume that markets have inverse linear demand and firms have quadratic production costs. First, we show that the resulting Cournot game has a unique equilibrium for any given network and provide a characterization of the production quantities at equilibrium. Our results identify a close connection between the equilibrium outcome and supply paths in the underlying network structure. In particular, we show that whether two firms see their output in different markets as strategic substitutes or complements depends critically on the paths between those markets in the line graph induced by the original bipartite network. Armed with a characterization of the equilibrium supply decisions, we explore the effect of changes in the network structure on firms' profits and consumer welfare. First, we study the question of a firm entering a new market. We show that entry may not be beneficial for either the firm or the consumers as such a move affects the entire vector of production quantities. The firm might face a more aggressive competition in its original markets due to its entry to a new market. Moreover, the effect on other firms and consumers also depends on their location in the network. This is in stark contrast with standard results in Cournot oligopoly where entry implies more competition in the market and thus higher consumer welfare. Similarly, the effect of a merger between two firms on profits and overall welfare largely depends on the structure of competition in the original Cournot market. In particular, we show that insights from analyzing mergers in a single market do not carry over in a networked environment. Market concentration indices are insufficient to correctly account for the network effect of a merger and one should not restrict attention to the set of markets that the firms participating in the merger supply to. Finally, we study the operations of a cartel including the entire set of firms. We show that the cartel maximizes its profits by appropriately segmenting the markets among its members so that a firm supplies solely to the ones allocated to it, and we provide an algorithm that computes the optimal production quantities for each firm in the cartel.","PeriodicalId":203155,"journal":{"name":"Proceedings of the fifteenth ACM conference on Economics and computation","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124587745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimal allocation without money: an engineering approach","authors":"I. Ashlagi, Peng Shi","doi":"10.2139/ssrn.2428449","DOIUrl":"https://doi.org/10.2139/ssrn.2428449","url":null,"abstract":"We study the optimal allocation of heterogeneous services without using monetary transfers. Agents have private, multi-dimensional utilities over the services, and a social planner has arbitrary priors on the utilities, which may depend on the agents' observable characteristics. The social planner's goal is to maximize a public objective, which may be complex, taking into account diverse considerations such as social welfare, equity, and system costs. Potential applications include the allocation of seats to public schools, spaces in college dorms or courses, and spots in subsidized housing. We propose an \"engineering\" approach to such problems, in which we simplify the analysis by considering a large-market model with a continuum of agents, and show using real data that a mechanism defined based on this approximation still yields good results in the finite market. In the large-market model, there are finitely many \"agent types,\" and a continuum of agents of each type. (Here, \"type\" corresponds to an agent's observable information, which is distinct from the private utilities.) The large market assumption implies that a mechanism can be decomposed into a collection of allocation rules, one for each type. We show that any allocation rule that satisfies incentive compatibility and Pareto optimality within type is representable as \"Competitive Equilibrium with Equal Incomes\" (CEEI). In other words, for each type of agents and for each service, there exists a \"virtual price\" for a unit of probability of getting that service, and the allocation is induced by giving each agent one unit of \"virtual money' and having them purchase their utility-maximizing probabilities to services. In addition, if the mechanism is restricted to being 'ordinal,' which means that it only uses preference rankings but not preference intensities, then an allocation rule that satisfies incentive compatibility and ordinal efficiency within type is 'lottery-plus-cutoff': each agent receives a uniformly random lottery number between zero and one, and for each service and each type, there is a 'lottery cutoff'; an agent is 'admitted' to a service if her lottery number is below the cutoff; each agent is allocated her most preferred service for which she is admitted. Such characterization results reduce the search of the optimal mechanism to a well-defined optimization over the prices and cutoffs for each type. We show how this large market approximation can be applied to an empirically relevant finite setting and yield good results. We consider the allocation of seats in public schools in Boston, which was a real problem faced by a city committee in the 2012-2013 Boston school assignment reform. Students are classified into 868 types by home location and there is a utility model for each type that comes from fitting a multinomial logit discrete choice model on previous years' data. There are 77 elementary schools with given capacities. Depending on their home location, a student is","PeriodicalId":203155,"journal":{"name":"Proceedings of the fifteenth ACM conference on Economics and computation","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133934026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strategy-proofness, investment efficiency, and marginal returns: an equivalence","authors":"J. Hatfield, F. Kojima, S. Kominers","doi":"10.2139/ssrn.2544951","DOIUrl":"https://doi.org/10.2139/ssrn.2544951","url":null,"abstract":"The market design literature has successfully designed mechanisms that achieve desirable properties such as strategy-proofness (incentive compatibility) and efficiency at the allocation stage. However, agents must often make investment decisions before participating in allocation mechanisms. These decisions are endogenous, in the sense that market participants' investments depend on the choice of mechanism. The goal of this paper is to understand when it is possible to design fully efficient mechanisms, i.e., mechanisms that both are efficient ex post and induce agents to make efficient investment decisions ex ante. To do so, we consider a general public choice setting (with transfers). Our framework includes, but is not limited to, object allocation settings such as auctions as well as two-sided matching environments such as residency matching. In our setting, payoffs depend not only on the outcome selected by the mechanism but also on agents' pre-mechanism investment choices. We say that a mechanism induces efficient investment by an agent if the investment choices that maximize the utility of that agent coincide with the investment choices that maximize social welfare. Our first main result shows that a mechanism induces efficient investment if and only if it provides marginal rewards, in the sense that the change in an agent's utility when that agent adjusts her investment is equal to the associated change in social welfare. For our second main result, we focus on ex post efficient mechanisms, i.e., mechanisms that select welfare-maximizing outcomes given agents' investment decisions. We show that for ex post efficient mechanisms, inducing efficient investment and providing marginal rewards are both equivalent to strategy-proofness. We extend our equivalence results to approximate versions of the aforementioned properties. Our results imply that under the Kelso--Crawford (1982) worker-optimal stable mechanism (with discrete transfers), workers are incentivized to make approximately efficient human capital investments before entering the labor market (conditional on the actions of firms).","PeriodicalId":203155,"journal":{"name":"Proceedings of the fifteenth ACM conference on Economics and computation","volume":"149 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133747969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}