{"title":"Ex-Post Equilibrium and VCG Mechanisms","authors":"R. Rozen, Rann Smorodinsky","doi":"10.1145/2594565","DOIUrl":"https://doi.org/10.1145/2594565","url":null,"abstract":"Consider an abstract social choice setting with incomplete information, where the number of alternatives is large. Albeit natural, implementing VCG mechanisms is infeasible due to the prohibitive communication constraints. However, if players restrict attention to a subset of the alternatives, feasibility may be recovered.\u0000 This article characterizes the class of subsets that induce an ex-post equilibrium in the original game. It turns out that a crucial condition for such subsets to exist is the availability of a type-independent optimal social alternative for each player. We further analyze the welfare implications of these restrictions.\u0000 This work follows that of Holzman et al. [2004] and Holzman and Monderer [2004] where similar analysis is done for combinatorial auctions.","PeriodicalId":194623,"journal":{"name":"ACM Trans. Economics and Comput.","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124317546","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":"An Equilibrium Analysis of Scrip Systems","authors":"Ian A. Kash, E. Friedman, Joseph Y. Halpern","doi":"10.1145/2659006","DOIUrl":"https://doi.org/10.1145/2659006","url":null,"abstract":"A game-theoretic model of scrip (artificial currency) systems is analyzed. It is shown that relative entropy can be used to characterize the distribution of agent wealth when all agents use threshold strategies—that is, they volunteer to do work if and only if they have below a threshold amount of money. Monotonicity of agents' best-reply functions is used to show that scrip systems have pure strategy equilibria where all agents use threshold strategies. An algorithm is given that can compute such an equilibrium and the resulting distribution of wealth.","PeriodicalId":194623,"journal":{"name":"ACM Trans. Economics and Comput.","volume":"55 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130739596","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":"Bounded-Distance Network Creation Games","authors":"Davide Bilò, Luciano Gualà, Guido Proietti","doi":"10.1145/2770639","DOIUrl":"https://doi.org/10.1145/2770639","url":null,"abstract":"A <i>network creation game</i> simulates a decentralized and noncooperative construction of a communication network. Informally, there are <i>n</i> players sitting on the network nodes, which attempt to establish a reciprocal communication by activating, thereby incurring a certain cost, any of their incident links. The goal of each player is to have all the other nodes as close as possible in the resulting network, while buying as few links as possible. According to this intuition, any model of the game must then appropriately address a balance between these two conflicting objectives. Motivated by the fact that a player might have a strong requirement about her centrality in the network, we introduce a new setting in which a player who maintains her (maximum or average) distance to the other nodes within a given bound incurs a cost equal to the number of activated edges; otherwise her cost is unbounded. We study the problem of understanding the structure of pure Nash equilibria of the resulting games, which we call M<scp>ax</scp>BD and S<scp>um</scp>BD, respectively. For both games, we show that when distance bounds associated with players are nonuniform, then equilibria can be arbitrarily bad. On the other hand, for M<scp>ax</scp>BD, we show that when nodes have a uniform bound <i>D</i> ≥ 3 on the maximum distance, then the <i>price of anarchy</i> (PoA) is lower and upper bounded by 2 and <i>O</i>(<i>n</i><sup>1/⌊log<sub>3</sub> <i>D</i> ⌋+1</sup>), respectively (i.e., PoA is constant as soon as <i>D</i> is Ω(<i>n</i><sup>ε</sup>), for any ε > 0), while for the interesting case <i>D</i>=2, we are able to prove that the PoA is Ω(&sqrt;<i>n</i>) and <i>O</i>(&sqrt;<i>n</i> log <i>n</i>). For the uniform S<scp>um</scp>BD, we obtain similar (asymptotically) results and moreover show that PoA becomes constant as soon as the bound on the average distance is 2<sup><i>ω</i>(&sqrt;log <i>n</i>)</sup>.","PeriodicalId":194623,"journal":{"name":"ACM Trans. Economics and Comput.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128528927","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":"Making Consensus Tractable","authors":"Elchanan Mossel, O. Tamuz","doi":"10.1145/2542174.2542176","DOIUrl":"https://doi.org/10.1145/2542174.2542176","url":null,"abstract":"We study a model of consensus decision making in which a finite group of Bayesian agents has to choose between one of two courses of action. Each member of the group has a private and independent signal at his or her disposal, giving some indication as to which action is optimal. To come to a common decision, the participants perform repeated rounds of voting. In each round, each agent casts a vote in favor of one of the two courses of action, reflecting his or her current belief, and observes the votes of the rest.\u0000 We provide an efficient algorithm for the calculation the agents have to perform and show that consensus is always reached and that the probability of reaching a wrong decision decays exponentially with the number of agents.","PeriodicalId":194623,"journal":{"name":"ACM Trans. Economics and Comput.","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115741421","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":"On Random Sampling Auctions for Digital Goods","authors":"S. Alaei, Azarakhsh Malekian, A. Srinivasan","doi":"10.1145/2517148","DOIUrl":"https://doi.org/10.1145/2517148","url":null,"abstract":"In the context of auctions for digital goods, an interesting random sampling auction has been proposed by Goldberg et al. [2001]. This auction has been analyzed by Feige et al. [2005], who have shown that it obtains in expectation at least 1/15 fraction of the optimal revenue, which is substantially better than the previously proven constant bounds but still far from the conjectured lower bound of 1/4. In this article, we prove that the aforementioned random sampling auction obtains at least 1/4 fraction of the optimal revenue for a large class of instances where the number of bids above (or equal to) the optimal sale price is at least 6. We also show that this auction obtains at least 1/4.68 fraction of the optimal revenue for the small class of remaining instances, thus leaving a negligible gap between the lower and upper bound. We employ a mix of probabilistic techniques and dynamic programming to compute these bounds.","PeriodicalId":194623,"journal":{"name":"ACM Trans. Economics and Comput.","volume":"188 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132417510","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}
Nima Haghpanah, Nicole Immorlica, V. Mirrokni, Kamesh Munagala
{"title":"Optimal Auctions with Positive Network Externalities","authors":"Nima Haghpanah, Nicole Immorlica, V. Mirrokni, Kamesh Munagala","doi":"10.1145/2465769.2465778","DOIUrl":"https://doi.org/10.1145/2465769.2465778","url":null,"abstract":"We consider the problem of designing auctions in social networks for goods that exhibit single-parameter submodular network externalities in which a bidder’s value for an outcome is a fixed private type times a known submodular function of the allocation of his friends. Externalities pose many issues that are hard to address with traditional techniques; our work shows how to resolve these issues in a specific setting of particular interest. We operate in a Bayesian environment and so assume private values are drawn according to known distributions. We prove that the optimal auction is NP-hard to approximate pointwise, and APX-hard on average. Thus we instead design auctions whose revenue approximates that of the optimal auction. Our main result considers step-function externalities in which a bidder’s value for an outcome is either zero, or equal to his private type if at least one friend has the good. For these settings, we provide a e/e + 1-approximation. We also give a 0.25-approximation auction for general single-parameter submodular network externalities, and discuss optimizing over a class of simple pricing strategies.","PeriodicalId":194623,"journal":{"name":"ACM Trans. Economics and Comput.","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115030061","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}
Abraham Othman, David M. Pennock, Daniel M. Reeves, T. Sandholm
{"title":"A Practical Liquidity-Sensitive Automated Market Maker","authors":"Abraham Othman, David M. Pennock, Daniel M. Reeves, T. Sandholm","doi":"10.1145/2509413.2509414","DOIUrl":"https://doi.org/10.1145/2509413.2509414","url":null,"abstract":"Automated market makers are algorithmic agents that enable participation and information elicitation in electronic markets. They have been widely and successfully applied in artificial-money settings, like some Internet prediction markets. Automated market makers from the literature suffer from two problems that contribute to their impracticality and impair their use beyond artificial-money settings: first, they are unable to adapt to liquidity, so that trades cause prices to move the same amount in both heavily and lightly traded markets, and second, in typical circumstances, they run at a deficit. In this article, we construct a market maker that is both sensitive to liquidity and can run at a profit. Our market maker has bounded loss for any initial level of liquidity and, as the initial level of liquidity approaches zero, worst-case loss approaches zero. For any level of initial liquidity we can establish a boundary in market state space such that, if the market terminates within that boundary, the market maker books a profit regardless of the realized outcome.","PeriodicalId":194623,"journal":{"name":"ACM Trans. Economics and Comput.","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128963415","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}
L. Blume, D. Easley, J. Kleinberg, Robert D. Kleinberg, É. Tardos
{"title":"Network formation in the presence of contagious risk","authors":"L. Blume, D. Easley, J. Kleinberg, Robert D. Kleinberg, É. Tardos","doi":"10.1145/1993574.1993576","DOIUrl":"https://doi.org/10.1145/1993574.1993576","url":null,"abstract":"There are a number of domains where agents must collectively form a network in the face of the following trade-off: each agent receives benefits from the direct links it forms to others, but these links expose it to the risk of being hit by a cascading failure that might spread over multi-step paths. Financial contagion, epidemic disease, and the exposure of covert organizations to discovery are all settings in which such issues have been articulated.\u0000 Here we formulate the problem in terms of strategic network formation, and provide asymptotically tight bounds on the welfare of both optimal and stable networks. We find that socially optimal networks are, in a precise sense, situated just beyond a phase transition in the behavior of the cascading failures, and that stable graphs lie slightly further beyond this phase transition, at a point where most of the available welfare has been lost. Our analysis enables us to explore such issues as the trade-offs between clustered and anonymous market structures, and it exposes a fundamental sense in which very small amounts of \"over-linking\" in networks with contagious risk can have strong consequences for the welfare of the participants.","PeriodicalId":194623,"journal":{"name":"ACM Trans. Economics and Comput.","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134489960","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 Mechanism Design without Money","authors":"A. Procaccia, Moshe Tennenholtz","doi":"10.1145/2542174.2542175","DOIUrl":"https://doi.org/10.1145/2542174.2542175","url":null,"abstract":"The literature on algorithmic mechanism design is mostly concerned with game-theoretic versions of optimization problems to which standard economic money-based mechanisms cannot be applied efficiently. Recent years have seen the design of various truthful approximation mechanisms that rely on payments. In this article, we advocate the reconsideration of highly structured optimization problems in the context of mechanism design. We explicitly argue for the first time that, in such domains, approximation can be leveraged to obtain truthfulness without resorting to payments. This stands in contrast to previous work where payments are almost ubiquitous and (more often than not) approximation is a necessary evil that is required to circumvent computational complexity.\u0000 We present a case study in approximate mechanism design without money. In our basic setting, agents are located on the real line and the mechanism must select the location of a public facility; the cost of an agent is its distance to the facility. We establish tight upper and lower bounds for the approximation ratio given by strategyproof mechanisms without payments, with respect to both deterministic and randomized mechanisms, under two objective functions: the social cost and the maximum cost. We then extend our results in two natural directions: a domain where two facilities must be located and a domain where each agent controls multiple locations.","PeriodicalId":194623,"journal":{"name":"ACM Trans. Economics and Comput.","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115642755","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}
京公网安备 11010802042870号
求助内容：
应助结果提醒方式：