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77
Impediments to Universal PreferenceBased Default Theories
 Artificial Intelligence
, 1989
"... Research on nonmonotonic and default reasoning has identified several important criteria for preferring alternative default inferences. The theories of reasoning based on each of these criteria may uniformly be viewed as theories of rational inference, in which the reasoner selects maximally preferr ..."
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Cited by 65 (11 self)
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Research on nonmonotonic and default reasoning has identified several important criteria for preferring alternative default inferences. The theories of reasoning based on each of these criteria may uniformly be viewed as theories of rational inference, in which the reasoner selects maximally preferred states of belief. Though researchers have noted some cases of apparent conflict between the preferences supported by different theories, it has been hoped that these special theories of reasoning may be combined into a universal logic of nonmonotonic reasoning. We show that the different categories of preferences conflict more than has been realized, and adapt formal results from social choice theory to prove that every universal theory of default reasoning will violate at least one reasonable principle of rational reasoning. Our results can be interpreted as demonstrating that, within the preferential framework, we cannot expect much improvement on the rigid lexicographic priority mechanisms that have been proposed for conflict resolution.
Determining Possible and Necessary Winners under Common Voting Rules Given Partial Orders
"... Usually a voting rule or correspondence requires agents to give their preferences as linear orders. However, in some cases it is impractical for an agent to give a linear order over all the alternatives. It has been suggested to let agents submit partial orders instead. Then, given a profile of part ..."
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Cited by 48 (13 self)
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Usually a voting rule or correspondence requires agents to give their preferences as linear orders. However, in some cases it is impractical for an agent to give a linear order over all the alternatives. It has been suggested to let agents submit partial orders instead. Then, given a profile of partial orders and a candidate c, two important questions arise: first, is c guaranteed to win, and second, is it still possible for c to win? These are the necessary winner and possible winner problems, respectively. We consider the setting where the number of alternatives is unbounded and the votes are unweighted. We prove that for Copeland, maximin, Bucklin, and ranked pairs, the possible winner problem is NPcomplete; also, we give a sufficient condition on scoring rules for the possible winner problem to be NPcomplete (Borda satisfies this condition). We also prove that for Copeland and ranked pairs, the necessary winner problem is coNPcomplete. All the hardness results hold even when the number of undetermined pairs in each vote is no more than a constant. We also present polynomialtime algorithms for the necessary winner problem for scoring rules, maximin, and Bucklin.
The power range assignment problem in radio networks on the plane
 Proc. 17th Annual Symposium on Theoretical Aspects of Computer Science (STACS
, 2000
"... Abstract. Given a finite set S of points (i.e. the stations of a radio network) on the plane and a positive integer 1 ≤ h ≤ S  −1, the 2d Min h R. Assign. problem consists of assigning transmission ranges to the stations so as to minimize the total power consumption provided that the transmission ..."
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Cited by 37 (9 self)
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Abstract. Given a finite set S of points (i.e. the stations of a radio network) on the plane and a positive integer 1 ≤ h ≤ S  −1, the 2d Min h R. Assign. problem consists of assigning transmission ranges to the stations so as to minimize the total power consumption provided that the transmission ranges of the stations ensure the communication between any pair of stations in at most h hops. We provide a lower bound on the total power consumption opt h (S) yielded by an optimal range assignment for any instance (S, h) of2d Min h R. Assign., for any positive constant h>0. The lower bound is a function of S, h and the minimum distance over all the pairs of stations in S. Then, we derive a constructive upper bound for the same problem as a function of S, h and the maximum distance over all the pairs of stations in S (i.e. the diameter of S). Finally, by combining the above bounds, we obtain a polynomialtime approximation algorithm for 2d Min h R. Assign. restricted to wellspread instances, for any positive constant h. Previous results for this problem were known only in special 1dimensional configurations (i.e. when points are arranged on a line).
Contingent Valuation: Controversies and Evidence
 ENVIRONMENTAL AND RESOURCE ECONOMICS
, 2001
"... Contingent valuation (CV) has become one of the most widely used nonmarket valuation techniques. CV’s prominence is due to its flexibility and ability to estimate total value, including passive use value. Its use and the inclusion of passive use value in benefitcost analyses and environmental li ..."
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Cited by 28 (1 self)
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Contingent valuation (CV) has become one of the most widely used nonmarket valuation techniques. CV’s prominence is due to its flexibility and ability to estimate total value, including passive use value. Its use and the inclusion of passive use value in benefitcost analyses and environmental litigation are the subject of a contentious debate. This paper discusses key areas of the debate over CV and the validity of passive use value. We conclude that many of the alleged problems with CV can be resolved by careful study design and implementation. We further conclude that claims that empirical CV findings are theoretically inconsistent are not generally supported by the literature. The debate over CV, however, has clarified several key issues related to nonmarket valuation and can provide useful guidance both to CV practitioners and the users of CV results.
Secure Multiparty Computation Goes Live ⋆
"... Abstract. In this note, we report on the first largescale and practical application of multiparty computation, which took place in January 2008. We also report on the novel cryptographic protocols that were used. 1 Introduction and History In multiparty computation (MPC), we consider a number of pl ..."
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Cited by 23 (1 self)
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Abstract. In this note, we report on the first largescale and practical application of multiparty computation, which took place in January 2008. We also report on the novel cryptographic protocols that were used. 1 Introduction and History In multiparty computation (MPC), we consider a number of players P1,..., Pn, who initially each hold inputs x1,..., xn, and we then want to securely compute some function f on these inputs, where f(x1,..., xn) = (y1,..., yn), such that Pi learns yi but no other information. This should hold, even if players exhibit some amount of adversarial behavior. The goal can be accomplished by an interactive
Implementation Theory
 in Kenneth Arrow, Amartya Sen, and Kataro Suzumara, eds., Handbook of Social Choice and Welfare, vol. I
, 2002
"... The implementation problem is the problem of designing a mechanism (game form) such that the equilibrium outcomes satisfy some criterion of social optimality. The early literature assumed that each agent would simply report his ..."
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Cited by 21 (1 self)
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The implementation problem is the problem of designing a mechanism (game form) such that the equilibrium outcomes satisfy some criterion of social optimality. The early literature assumed that each agent would simply report his
Social software
 Synthese
, 2001
"... We suggest that the issue of constructing and verifying social procedures, which we suggestively call social software, be pursued as systematically as computer software is pursued by computer scientists. Certain complications do arise with social software which do not arise with computer software, b ..."
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Cited by 19 (4 self)
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We suggest that the issue of constructing and verifying social procedures, which we suggestively call social software, be pursued as systematically as computer software is pursued by computer scientists. Certain complications do arise with social software which do not arise with computer software, but the similarities are nonetheless strong, and tools already exist which would enable us to start work on this important project. We give a variety of suggestive examples and indicate some theoretical work which already exists. I send someone shopping. I give him a slip marked “five red apples”. He takes the slip to the shopkeeper who opens a drawer marked “apples”; then he looks up the word “red ” in a table and finds a colour sample opposite it; then he says the series of cardinal numbers – I assume he knows them by heart – up to the word “five ” and for each number he takes an apple of the same colour as the sample out of the drawer. “But what is the “meaning of the word ‘five’? ” No such thing was in question here, only how the word “five ” is used. In this passage from the Philosophical Investigations Wittgenstein is describing a social algorithm, albeit a simple one. He also introduces the notion of a data type (though not by that name) which is now quite important in computer algorithms. The words “apple”, “red”, “five ” belong to different data types and are used in very different ways. This variety forms a sharp contrast to the uniformity of objects in set theory, where everything, natural numbers, reals, etc. are constructed from the same basic material. But it does form a parallel to the variety we find in computer algorithms. In computer algorithms we also find integers, stacks, queues, and pointers which play different sorts of roles. Wittgenstein’s purpose in his example is to wean us away from the notion that there is just one kind of thing – meaning – which explains all different kinds of words, and he uses 1
Voting under Constraints
 JOURNAL OF ECONOMIC LITERATURE
, 1997
"... We consider a broad class of situations where a society must choose from a finite set of alternatives. This class includes, as polar cases, those where the preferences of agents are completely unrestricted and those where their preferences are singlepeaked. We prove that strategyproof mechanisms i ..."
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Cited by 15 (2 self)
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We consider a broad class of situations where a society must choose from a finite set of alternatives. This class includes, as polar cases, those where the preferences of agents are completely unrestricted and those where their preferences are singlepeaked. We prove that strategyproof mechanisms in all these domains must be based on a generalization of the median voter principle. Moreover, they must satisfy a property, to be called the "intersection property," which becomes increasingly stringent as the preference domain is enlarged. In most applications, our results precipitate impossibility theorems. In particular, they imply the Gibbard Satterthwaite theorem as a corollary.