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115
An Efficient Reduction of Ranking to Classification
, 2007
"... This paper describes an efficient reduction of the learning problem of ranking to binary classification. The reduction is randomized and guarantees a pairwise misranking regret bounded by that of the binary classifier, improving on a recent result of Balcan et al. (2007) which ensures only twice tha ..."
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Cited by 11 (2 self)
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This paper describes an efficient reduction of the learning problem of ranking to binary classification. The reduction is randomized and guarantees a pairwise misranking regret bounded by that of the binary classifier, improving on a recent result of Balcan et al. (2007) which ensures only twice that upperbound. Moreover, our reduction applies to a broader class of ranking loss functions, admits a simple proof, and the expected time complexity of our algorithm in terms of number of calls to a classifier or preference function is also improved from Ω(n 2) to O(n log n). In addition, when the top k ranked elements only are required (k ≪ n), as in many applications in information extraction or search engine design, the time complexity of our algorithm can be further reduced to O(k log k+n). Our reduction and algorithm are thus practical for realistic applications where the number of points to rank exceeds several thousands. Much of our results also extend beyond the bipartite case previously studied. To further complement them, we also derive lower bounds for any deterministic reduction of ranking to binary classification, proving that randomization is necessary to achieve our reduction guarantees. 1
A Maximum Likelihood Approach towards Aggregating Partial Orders
 PROCEEDINGS OF THE TWENTYSECOND INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE
"... In many of the possible applications as well as the theoretical models of computational social choice, the agents ’ preferences are represented as partial orders. In this paper, we extend the maximum likelihood approach for defining “optimal ” voting rules to this setting. We consider distributions ..."
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Cited by 10 (4 self)
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In many of the possible applications as well as the theoretical models of computational social choice, the agents ’ preferences are represented as partial orders. In this paper, we extend the maximum likelihood approach for defining “optimal ” voting rules to this setting. We consider distributions in which the pairwise comparisons/incomparabilities between alternatives are drawn i.i.d. We call such models pairwiseindependent models and show that they correspond to a class of voting rules that we call pairwise scoring rules. This generalizes rules such as Kemeny and Borda. Moreover, we show that Borda is the only pairwise scoring rule that satisfies neutrality, when the outcome space is the set of all alternatives. We then study which voting rules defined for linear orders can be extended to partial orders via our MLE model. We show that any weakly neutral outcome scoring rule (including any ranking/candidate scoring rule) based on the weighted majority graph can be represented as the MLE of a weakly neutral pairwiseindependent model. Therefore, all such rules admit natural extensions to profiles of partial orders. Finally, we propose a specific MLE model πk for generating a set of k winning alternatives, and study the computational complexity of winner determination for the MLE of πk.
Computeraided proofs of Arrow’s and other impossibility theorems
 Artificial Intelligence
, 2009
"... Arrow’s Impossibility Theorem is one of the landmark results in social choice theory. Over the years since the theorem was proved in 1950, quite a few alternative proofs have been put forward. In this paper, we propose yet another alternative proof of the theorem. The basic idea is to use induction ..."
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Cited by 9 (2 self)
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Arrow’s Impossibility Theorem is one of the landmark results in social choice theory. Over the years since the theorem was proved in 1950, quite a few alternative proofs have been put forward. In this paper, we propose yet another alternative proof of the theorem. The basic idea is to use induction to reduce the theorem to the base case with 3 alternatives and 2 agents and then use computers to verify the base case. This turns out to be an effective approach for proving other impossibility theorems such as Sen’s and MullerSatterthwaite’s theorems as well. Furthermore, we believe this new proof opens an exciting prospect of using computers to discover similar impossibility or even possibility results.
The Unavailable Candidate Model: A DecisionTheoretic View of Social Choice
"... One of the fundamental problems in the theory of social choice is aggregating the rankings of a set of agents (or voters) into a consensus ranking. Rank aggregation has found application in a variety of computational contexts. However, the goal of constructing a consensus ranking rather than, say, a ..."
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Cited by 8 (5 self)
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One of the fundamental problems in the theory of social choice is aggregating the rankings of a set of agents (or voters) into a consensus ranking. Rank aggregation has found application in a variety of computational contexts. However, the goal of constructing a consensus ranking rather than, say, a single outcome (or winner) is often left unjustified, calling into question the suitability of classical rank aggregation methods. We introduce a novel model which offers a decisiontheoretic motivation for constructing a consensus ranking. Our unavailable candidate model assumes that a consensus choice must be made, but that candidates may become unavailable after voters express their preferences. Roughly speaking, a consensus ranking serves as a compact, easily communicable representation of a decision policy that can be used to make choices in the face of uncertain candidate availability. We use this model to define a principled aggregation method that minimizes expected voter dissatisfaction with the chosen candidate. We give exact and approximation algorithms for computing optimal rankings and provide computational evidence for the effectiveness of a simple greedy scheme. We also describe strong connections to popular voting protocols such as the plurality rule and the Kemeny consensus, showing specifically that Kemeny produces optimal rankings in the unavailable candidate model under certain conditions.
Interpersonally Comparable Utility
, 1998
"... : This chapte supple.D tsthe ee59 re59 in Hammond (1991a) and Suzumura (1996) byconce trating on fourissueUE. first is that in weR fare ere99.D inteK eKKR9 comparisonsare onlyney.E to go be yond PareK eeKk9. or PareU improveKx ts.The seThe conce. the ne for inteR pekx5k comparisons ..."
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Cited by 8 (4 self)
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: This chapte supple.D tsthe ee59 re59 in Hammond (1991a) and Suzumura (1996) byconce trating on fourissueUE. first is that in weR fare ere99.D inteK eKKR9 comparisonsare onlyney.E to go be yond PareK eeKk9. or PareU improveKx ts.The seThe conce. the ne for inteR pekx5k comparisons in social choice thee , toeEUK e Arrow's impossibility theRk.DEk thirdissue is how tore55U Arrow'sinde edexK ofirre5 ant altek.DE e condition so that inteK eKKU comparisons can be accommodatem Finally, and most important,the chapte pree ts a form of utilitarianism in which inte9 e95RE comparisons can be inteEE5R5. ase.E95 pre95.DEE for di#eK t pek9k characteEKx.e 22 INTRODUCTION AND OUTLINE Over many years, interpersonal comparisons of utility have had a significant role to play in economics. Utility began as a concept which Frances Hutcheson, Cesare Beccaria, Jeremy Bentham, John Stuart Mill, and Henry Sidgwick sought to use as a basis for a general ethical theory tha...
The corporate objective revisited
 Organization Science
, 2004
"... The stock market convulsions and corporate scandals of 2001 and 2002 have reignited debates on the purposes of the corporation, in particular, the goal of shareholder value maximization. We revisit the debates, reexamine the traditional rationales, and develop a set of new arguments for why the pre ..."
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Cited by 8 (0 self)
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The stock market convulsions and corporate scandals of 2001 and 2002 have reignited debates on the purposes of the corporation, in particular, the goal of shareholder value maximization. We revisit the debates, reexamine the traditional rationales, and develop a set of new arguments for why the preferred objective function for the corporation must unambiguously continue to be the one that says ‘maximize shareholder value. ’ We trace the origins of the debates from the late nineteenth century, their implications for accepted law and practice of corporate governance in the United States, and their reflection in shareholder versus stakeholder views in the organization studies literature and contractarian versus communitarian views in the legal literature. We address in detail possible critiques of the shareholder value maximization view. While we recognize certain boundary constraints to our arguments, we conclude that the issues raised by such critiques and constraints are not unique to the shareholder value maximization view, but will exist even if the firm is managed on behalf of nonshareowning stakeholders. We are grateful for comments from the journal reviewers, and from Michael Bradley, Anthony Frost, Vijay
Goals, Desires, Utilities and Preferences
, 1998
"... . In this paper we study the logic of goals, which are formalized as desires with an utilitarian semantics. In our framework goals have a dual character, because they are constraints on utility functions as well as constructors of these utility functions. The nonmonotonic reasoning related to the c ..."
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Cited by 7 (5 self)
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. In this paper we study the logic of goals, which are formalized as desires with an utilitarian semantics. In our framework goals have a dual character, because they are constraints on utility functions as well as constructors of these utility functions. The nonmonotonic reasoning related to the constructors reflects that goals are used as heuristic approximations of preferences in decision making and planning. Moreover, our framework is based on bipolar additive preferences, where bipolarity means that goals can either result in a gain of utility if achieved, or a loss of utility if not achieved. The framework is used to illustrate different types of contextdependence and conflicts of goals. 1 Introduction Decision theory has become widely accepted in the AI community as a useful framework for planning and decision making [9]. In the context of qualitative decision theory [15, 18, 2] recently several logics for goals and desires have been proposed [8, 7, 3, 15, 17, 16, 14, 12, 20...
A complexityofstrategicbehavior comparison between Schulze’s rule and ranked pairs
 In Proc. of 26th AAAI Conference on AI
, 2012
"... Schulze’s rule and ranked pairs are two Condorcet methods that both satisfy many natural axiomatic properties. Schulze’s rule is used in the elections of many organizations, including ..."
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Cited by 7 (0 self)
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Schulze’s rule and ranked pairs are two Condorcet methods that both satisfy many natural axiomatic properties. Schulze’s rule is used in the elections of many organizations, including
Paper rating vs. paper ranking
 In WOWCS’08, Workshop on Organizing Workshops, Conferences, and Symposia for Computer Systems
, 1984
"... Within the computerscience community, submitted conference papers are typically evaluated by means of rating, in two respects: First, individual reviewers are asked to provide their evaluations of papers by assigning a rating to each paper’s overall quality. Second, program committees collectively ..."
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Cited by 6 (0 self)
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Within the computerscience community, submitted conference papers are typically evaluated by means of rating, in two respects: First, individual reviewers are asked to provide their evaluations of papers by assigning a rating to each paper’s overall quality. Second, program committees collectively rate each paper as being either worthy or unworthy of acceptance, according to the aggregate judgment of the committee members. This paper proposes an alternative approach to these two processes, based on rankings rather than ratings. 1.
Discounting climate change damages: Working note for the Stern review
, 2006
"... This working note provides a basic overview of discounting in the context of climate change policy. After defining the social discount factor and social discount rate in terms of shadow prices (section 2), and noting the limitations of costbenefit analysis for climate change (section 3), the determ ..."
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Cited by 5 (0 self)
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This working note provides a basic overview of discounting in the context of climate change policy. After defining the social discount factor and social discount rate in terms of shadow prices (section 2), and noting the limitations of costbenefit analysis for climate change (section 3), the determination of efficient social discount rates is discussed given: the impact of uncertainty about future economic conditions (section 4.2), the effect of heterogeneous time preferences (4.3) and time inconsistency issues (4.4). Fairness between generations is then discussed (5.1) and some alternatives to using discount factors are considered (5.2). It is concluded that the shadow discount rate should be declining over time to reflect the certaintyequivalent path. It is also argued that the underlying utility discount rate is very small, possibly zero to a first approximation.