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17
A Tractable and Expressive Class of Marginal Contribution Nets and Its Applications
, 2008
"... Coalitional games raise a number of important questions from the point of view of computer science, key among them being how to represent such games compactly, and how to efficiently compute solution concepts assuming such representations. Marginal contribution nets (MCnets), introduced by Ieong an ..."
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Cited by 24 (3 self)
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Coalitional games raise a number of important questions from the point of view of computer science, key among them being how to represent such games compactly, and how to efficiently compute solution concepts assuming such representations. Marginal contribution nets (MCnets), introduced by Ieong and Shoham, are one of the simplest and most influential representation schemes for coalitional games. MCnets are a rulebased formalism, in which rules take the form pattern − → value, where “pattern ” is a Boolean condition over agents, and “value ” is a numeric value. Ieong and Shoham showed that, for a class of what we will call “basic” MCnets, where patterns are constrained to be a conjunction of literals, marginal contribution nets permit the easy computation of solution concepts such as the Shapley value. However, there are very natural classes of coalitional game that
From Preference Logics to Preference Languages, and Back
"... Preference logics and AI preference representation languages are both concerned with reasoning about preferences on combinatorial domains, yet so far these two streams of research have had little interaction. This paper contributes to the bridging of these areas. We start by constructing a “prototyp ..."
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Cited by 15 (2 self)
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Preference logics and AI preference representation languages are both concerned with reasoning about preferences on combinatorial domains, yet so far these two streams of research have had little interaction. This paper contributes to the bridging of these areas. We start by constructing a “prototypical” preference logic, which combines features of existing preference logics, and then we show that many wellknown preference languages, such as CPnets and its extensions, are natural fragments of it. After establishing useful characterizations of dominance and consistency in our logic, we study the complexity of satisfiability in the general case as well as for meaningful fragments, and we study the expressive power as well as the relative succinctness of some of these fragments. 1.
Simple Negotiation Schemes for Agents with Simple Preferences: Sufficiency, Necessity and Maximality
 JOURNAL OF AUTONOMOUS AGENTS AND MULTIAGENT SYSTEMS
, 2009
"... We investigate the properties of an abstract negotiation framework where agents autonomously negotiate over allocations of indivisible resources. In this framework, reaching an allocation that is optimal may require very complex multilateral deals. Therefore, we are interested in identifying classe ..."
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Cited by 12 (5 self)
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We investigate the properties of an abstract negotiation framework where agents autonomously negotiate over allocations of indivisible resources. In this framework, reaching an allocation that is optimal may require very complex multilateral deals. Therefore, we are interested in identifying classes of valuation functions such that any negotiation conducted by means of deals involving only a single resource at a time is bound to converge to an optimal allocation whenever all agents model their preferences using these functions. In the case of negotiation with monetary side payments amongst selfinterested but myopic agents, the class of modular valuation functions turns out to be such a class. That is, modularity is a sufficient condition for convergence in this framework. We also show that modularity is not a necessary condition. Indeed, there can be no condition on individual valuation functions that would be both necessary and sufficient in this sense. Evaluating conditions formulated with respect to the whole profile of valuation functions used by the agents in the system would be possible in theory, but turns out to be computationally intractable in practice. Our main result shows that the class of modular functions is maximal in the sense that no strictly larger class of valuation functions would still guarantee an optimal outcome of negotiation, even when we permit more general bilateral deals. We also establish similar results in the context of negotiation without side payments.
Voting Almost Maximizes Social Welfare Despite Limited Communication
"... In cooperative multiagent systems an alternative that maximizes the social welfare—the sum of utilities—can only be selected if each agent reports its full utility function. This may be infeasible in environments where communication is restricted. Employing a voting rule to choose an alternative gre ..."
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Cited by 9 (5 self)
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In cooperative multiagent systems an alternative that maximizes the social welfare—the sum of utilities—can only be selected if each agent reports its full utility function. This may be infeasible in environments where communication is restricted. Employing a voting rule to choose an alternative greatly reduces the communication burden, but leads to a possible gap between the social welfare of the optimal alternative and the social welfare of the one that is ultimately elected. Procaccia and Rosenschein (2006) have introduced the concept of distortion to quantify this gap. In this paper, we present the notion of embeddings into voting rules: functions that receive an agent’s utility function and return the agent’s vote. We establish that very low distortion can be obtained using randomized embeddings, especially when the number of agents is large compared to the number of alternatives. We investigate our ideas in the context of three prominent voting rules with low communication costs: Plurality, Approval, and Veto. Our results arguably provide a compelling reason for employing voting in cooperative multiagent systems.
Modelling combinatorial auctions in linear logic
 in Proc. 12th International Conference on the Principles of Knowledge Representation and Reasoning (KR2010
, 2010
"... We show that linear logic can serve as an expressive framework in which to model a rich variety of combinatorial auction mechanisms. Due to its resourcesensitive nature, linear logic can easily represent bids in combinatorial auctions in which goods may be sold in multiple units, and we show how it ..."
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Cited by 8 (5 self)
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We show that linear logic can serve as an expressive framework in which to model a rich variety of combinatorial auction mechanisms. Due to its resourcesensitive nature, linear logic can easily represent bids in combinatorial auctions in which goods may be sold in multiple units, and we show how it naturally generalises several bidding languages familiar from the literature. Moreover, the winner determination problem, i.e., the problem of computing an allocation of goods to bidders producing a certain amount of revenue for the auctioneer, can be modelled as the problem of finding a proof for a particular linear logic sequent.
Nash Social Welfare in Multiagent Resource Allocation
"... Abstract. We study different aspects of the multiagent resource allocation problem when the objective is to find an allocation that maximizes Nash social welfare, the product of the utilities of the individual agents. The Nash solution is an important welfare criterion that combines efficiency and f ..."
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Cited by 5 (1 self)
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Abstract. We study different aspects of the multiagent resource allocation problem when the objective is to find an allocation that maximizes Nash social welfare, the product of the utilities of the individual agents. The Nash solution is an important welfare criterion that combines efficiency and fairness considerations. We show that the problem of finding an optimal outcome is NPhard for a number of different languages for representing agent preferences; we establish new results regarding convergence to Nashoptimal outcomes in a distributed negotiation framework; and we design and test algorithms similar to those applied in combinatorial auctions for computing such an outcome directly. 1
Reduction of Economic Inequality in Combinatorial Domains
"... Criteria for measuring economic inequality, such as the Lorenz curve and the Gini index, are widely used in the social sciences but have hardly been explored in Multiagent Systems, even though the significance of other concepts from fair division is widely accepted in the field. In a departure from ..."
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Cited by 2 (1 self)
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Criteria for measuring economic inequality, such as the Lorenz curve and the Gini index, are widely used in the social sciences but have hardly been explored in Multiagent Systems, even though the significance of other concepts from fair division is widely accepted in the field. In a departure from the standard model used in Economics, we apply inequality criteria to allocation problems with indivisible goods, i.e., to the kind of problem typically analysed in Multiagent Systems. This gives rise to the combinatorial optimisation problem of computing an allocation that reduces inequality with respect to an initial allocation (and the closely related problem of minimising inequality), for a chosen inequality measure. We define this problem, we discuss the computational complexity of various aspects of it, and we formulate a generic approach to designing modular algorithms for solving it using integer programming.
Logic and Social Choice Theory
"... We give an introduction to social choice theory, the formal study of mechanisms for collective decision making, and highlight the role that logic has taken, and continues to take, in its development. The first part of the chapter is devoted to a succinct exposition of the axiomatic method in social ..."
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Cited by 1 (1 self)
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We give an introduction to social choice theory, the formal study of mechanisms for collective decision making, and highlight the role that logic has taken, and continues to take, in its development. The first part of the chapter is devoted to a succinct exposition of the axiomatic method in social choice theory and covers several of the classical theorems in the field. In the second part we then outline three areas of recent research activity: logics for social choice, social choice in combinatorial domains, and judgment aggregation.
1Nash Social Welfare in Multiagent Resource Allocation
"... Summary. We study different aspects of the multiagent resource allocation problem when the objective is to find an allocation that maximizes Nash social welfare, the product of the utilities of the individual agents. The Nash solution is an important welfare criterion that combines efficiency and ..."
Abstract
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Summary. We study different aspects of the multiagent resource allocation problem when the objective is to find an allocation that maximizes Nash social welfare, the product of the utilities of the individual agents. The Nash solution is an important welfare criterion that combines efficiency and fairness considerations. We show that the problem of finding an optimal outcome is NPhard for a number of different languages for representing agent preferences; we establish new results regarding convergence to Nashoptimal outcomes in a distributed negotiation framework; and we design and test algorithms similar to those applied in combinatorial auctions for computing such an outcome directly. 1.1