Trials of Characterizations of Anti-Manipulation Method⋆
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Are Condorcet and Minimax Voting Systems the Best?1
1 Are Condorcet and Minimax Voting Systems the Best?1 Richard B. Darlington Cornell University Abstract For decades, the minimax voting system was well known to experts on voting systems, but was not widely considered to be one of the best systems. But in recent years, two important experts, Nicolaus Tideman and Andrew Myers, have both recognized minimax as one of the best systems. I agree with that. This paper presents my own reasons for preferring minimax. The paper explicitly discusses about 20 systems. Comments invited. [email protected] Copyright Richard B. Darlington May be distributed free for non-commercial purposes Keywords Voting system Condorcet Minimax 1. Many thanks to Nicolaus Tideman, Andrew Myers, Sharon Weinberg, Eduardo Marchena, my wife Betsy Darlington, and my daughter Lois Darlington, all of whom contributed many valuable suggestions. 2 Table of Contents 1. Introduction and summary 3 2. The variety of voting systems 4 3. Some electoral criteria violated by minimax’s competitors 6 Monotonicity 7 Strategic voting 7 Completeness 7 Simplicity 8 Ease of voting 8 Resistance to vote-splitting and spoiling 8 Straddling 8 Condorcet consistency (CC) 8 4. Dismissing eight criteria violated by minimax 9 4.1 The absolute loser, Condorcet loser, and preference inversion criteria 9 4.2 Three anti-manipulation criteria 10 4.3 SCC/IIA 11 4.4 Multiple districts 12 5. Simulation studies on voting systems 13 5.1. Why our computer simulations use spatial models of voter behavior 13 5.2 Four computer simulations 15 5.2.1 Features and purposes of the studies 15 5.2.2 Further description of the studies 16 5.2.3 Results and discussion 18 6. -
A Canadian Model of Proportional Representation by Robert S. Ring A
Proportional-first-past-the-post: A Canadian model of Proportional Representation by Robert S. Ring A thesis submitted to the School of Graduate Studies in partial fulfilment of the requirements for the degree of Master of Arts Department of Political Science Memorial University St. John’s, Newfoundland and Labrador May 2014 ii Abstract For more than a decade a majority of Canadians have consistently supported the idea of proportional representation when asked, yet all attempts at electoral reform thus far have failed. Even though a majority of Canadians support proportional representation, a majority also report they are satisfied with the current electoral system (even indicating support for both in the same survey). The author seeks to reconcile these potentially conflicting desires by designing a uniquely Canadian electoral system that keeps the positive and familiar features of first-past-the- post while creating a proportional election result. The author touches on the theory of representative democracy and its relationship with proportional representation before delving into the mechanics of electoral systems. He surveys some of the major electoral system proposals and options for Canada before finally presenting his made-in-Canada solution that he believes stands a better chance at gaining approval from Canadians than past proposals. iii Acknowledgements First of foremost, I would like to express my sincerest gratitude to my brilliant supervisor, Dr. Amanda Bittner, whose continuous guidance, support, and advice over the past few years has been invaluable. I am especially grateful to you for encouraging me to pursue my Master’s and write about my electoral system idea. -
Majority Judgment: a New Voting Method
Paradoxes Impossbilities Majority Judgment Theory Applications of MJ Logiciels JM Experimental Evidences Conclusion Majority Judgment: A New Voting Method Rida Laraki CNRS (Lamsade, Dauphine) and University of Liverpool Colloquium J. Morgenstern, INRIA, Sophia-Antipolis December 11, 2018 (Joint work with Michel Balinski) R. Laraki Majority Judgment: A New Voting Method Paradoxes Impossbilities Majority Judgment Theory ApplicationsMethods of MJ Logiciels of Voting JM Paradoxes Experimental in Theory Evidences Paradoxes Conclusion in Practice 1 Paradoxes Methods of Voting Paradoxes in Theory Paradoxes in Practice 2 Impossbilities May’s Axioms for Two Candidates Arrow’s Impossibility Theorem 3 Majority Judgment From Practice Small Jury Large Electorate 4 Theory Domination Paradox Possibility Manipulation 5 Applications of MJ Trump 2016 Gillets Jaunes Délé´gué CM1 6 Logiciels JM 7 Experimental Evidences 8 Conclusion R. Laraki Majority Judgment: A New Voting Method First-past-the-post: also called plurality voting, used in UK, US and Canada to elect members of house of representatives. A voter designate one candidate. The most designated wins. Two-past-the-post: used in France and several countries (Finland, Austria, Russia, Portugal, Ukraine, etc) to elect the president. A voter designates one candidate. If a candidate is designated by a majority, he is elected. Otherwise, there is a run-off between the two first candidates. Paradoxes Impossbilities Majority Judgment Theory ApplicationsMethods of MJ Logiciels of Voting JM Paradoxes Experimental in Theory Evidences Paradoxes Conclusion in Practice Voting methods most used in elections R. Laraki Majority Judgment: A New Voting Method A voter designate one candidate. The most designated wins. Two-past-the-post: used in France and several countries (Finland, Austria, Russia, Portugal, Ukraine, etc) to elect the president. -
A Treasury System for Cryptocurrencies: Enabling Better Collaborative Intelligence ⋆
A Treasury System for Cryptocurrencies: Enabling Better Collaborative Intelligence ? Bingsheng Zhang1, Roman Oliynykov2, and Hamed Balogun3 1 Lancaster University, UK [email protected] 2 Input Output Hong Kong Ltd. [email protected] 3 Lancaster University, UK [email protected] Abstract. A treasury system is a community controlled and decentralized collaborative decision- making mechanism for sustainable funding of the blockchain development and maintenance. During each treasury period, project proposals are submitted, discussed, and voted for; top-ranked projects are funded from the treasury. The Dash governance system is a real-world example of such kind of systems. In this work, we, for the first time, provide a rigorous study of the treasury system. We modelled, designed, and implemented a provably secure treasury system that is compatible with most existing blockchain infrastructures, such as Bitcoin, Ethereum, etc. More specifically, the proposed treasury system supports liquid democracy/delegative voting for better collaborative intelligence. Namely, the stake holders can either vote directly on the proposed projects or delegate their votes to experts. Its core component is a distributed universally composable secure end-to-end verifiable voting protocol. The integrity of the treasury voting decisions is guaranteed even when all the voting committee members are corrupted. To further improve efficiency, we proposed the world's first honest verifier zero-knowledge proof for unit vector encryption with logarithmic size communication. This partial result may be of independent interest to other cryptographic protocols. A pilot system is implemented in Scala over the Scorex 2.0 framework, and its benchmark results indicate that the proposed system can support tens of thousands of treasury participants with high efficiency. -
Automated Verification for Functional and Relational Properties of Voting
Automated Verification for Functional and Relational Properties of Voting Rules Bernhard Beckert, Thorsten Bormer, Michael Kirsten, Till Neuber, and Mattias Ulbrich Abstract In this paper, we formalise classes of axiomatic properties for voting rules, discuss their characteristics, and show how symmetry properties can be exploited in the verification of other properties. Following that, we describe how automated verification methods such as software bounded model checking and deductive verification can be used to verify implementations of voting rules. We present a case study, where we use and compare different approaches to verify that plurality voting satisfies the majority and the anonymity property. 1 Introduction Axiomatic definitions of characteristic properties for voting rules are important both for understanding existing voting rules and for designing new ones. For the trustworthiness of elections, it is also important to analyse the algorithmic descriptions of voting rules and to prove that they have the desired properties, i.e., they satisfy the declarative description. There are two classes of voting rule properties, namely (a) functional (absolute) properties, such as the majority criterion, which refer to single voting results, and (b) relational properties, such as anonymity, which are defined by comparing two (or more) results. In this paper, we first formally define these two classes of properties and discuss their characteristics (Section 2). We then show how symmetry properties { which are a particular kind of relational properties { can be exploited to more efficiently verify voting rules w.r.t. other (functional) properties (Section 3). Proving properties of voting rules by hand is tedious and error-prone { in particular, if the rules and properties evolve during design and various versions have to be verified. -
Majority Judgment Vs. Majority Rule ∗
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by University of Liverpool Repository Majority Judgment vs. Majority Rule ∗ Michel Balinski CNRS, CREST, Ecole´ Polytechnique, France, [email protected] and Rida Laraki* CNRS, University of Paris Dauphine-PSL, France, [email protected] and University of Liverpool, United Kingdom June 6, 2019 Abstract The validity of majority rule in an election with but two candidates|and so also of Condorcet consistency| is challenged. Axioms based on evaluating candidates|paralleling those of K. O. May characterizing ma- jority rule for two candidates based on comparing candidates|lead to another method, majority judgment, that is unique in agreeing with the majority rule on pairs of \polarized" candidates. It is a practical method that accommodates any number of candidates, avoids both the Condorcet and Arrow paradoxes, and best resists strategic manipulation. Key words: majority, measuring, ranking, electing, Condorcet consistency, domination paradox, tyranny of majority, intensity problem, majority-gauge, strategy-proofness, polarization. 1 Introduction Elections measure. Voters express themselves, a rule amalgamates them, the candidates' scores|measures of support|determine their order of finish, and the winner. Traditional methods ask voters to express themselves by comparing them: • ticking one candidate at most (majority rule, first-past-the-post) or several candidates (approval voting), candidates' total ticks ranking them; • rank-ordering the candidates (Borda rule, alternative vote or preferential voting, Llull's rule, Dasgupta- Maskin method, . ), differently derived numerical scores ranking them. However, no traditional method measures the support of one candidate.1 Instead, the theory of voting (or of social choice) elevates to a basic distinguishing axiom the faith that in an election between two candidates majority rule is the only proper rule. -
Game Theory and Democracy Homework Problems
Game Theory and Democracy Homework Problems PAGE 82 Challenge Problem: Show that any voting model (such as the Unit Interval Model or the Unit Square Model) which has a point symmetry always has a Condorcet winner for every election, namely the candidate who is closest to the point of symmetry! PAGE 93 Exercise: Show that if there are not any cycles of any length in the preferences of the voters, then there must be a Condorcet winner. (Don’t worry about making your proof rigorous, just convince yourself of this fact, to the point you could clearly explain your ideas to someone else.) PAGE 105 Exercise: Prove that the strongest chain strength of a chain from Candidate Y to Candidate X is 3. (If you can convince a skeptical friend that it is true, then that is a proof.) Exercise: Prove that it is never necessary to use a candidate more than once to find a chain with the strongest chain strength between two candidates. Hint: Show that whenever there is a loop, like the one shown in red Y (7) Z (3) W (9) Y (7) Z (3) W (11) X, we can consider a shortened chain by simply deleting the red loop Y (7) Z (3) W (11) X which is at least as strong as the original loop. Exercises: Prove that all of the chains above are in fact strongest chains, as claimed. Hint: The next figure, which has all of the information of the margin of victory matrix, will be useful, and is the type of figure you may choose to draw for yourself for other elections, from time to time. -
Crowdsourcing Applications of Voting Theory Daniel Hughart
Crowdsourcing Applications of Voting Theory Daniel Hughart 5/17/2013 Most large scale marketing campaigns which involve consumer participation through voting makes use of plurality voting. In this work, it is questioned whether firms may have incentive to utilize alternative voting systems. Through an analysis of voting criteria, as well as a series of voting systems themselves, it is suggested that though there are no necessarily superior voting systems there are likely enough benefits to alternative systems to encourage their use over plurality voting. Contents Introduction .................................................................................................................................... 3 Assumptions ............................................................................................................................... 6 Voting Criteria .............................................................................................................................. 10 Condorcet ................................................................................................................................. 11 Smith ......................................................................................................................................... 14 Condorcet Loser ........................................................................................................................ 15 Majority ................................................................................................................................... -
Democracy Without Elections Mainz
Democracy without Elections: Is electoral accountability essential for democracy? Felix Gerlsbeck [email protected] Paper prepared for the workshop “Democratic Anxiety. Democratic Resilience.” Mainz, 15-17 June 2017 DRAFT VERSION, PLEASE DO NOT CITE WITHOUT AUTHOR’S PERMISSION 1. Introduction The idea of choosing political decision-makers by sortition, that is, choosing them randomly from a pool of the entire population or from some qualified subset, through some form of lottery or other randomizing procedure, is familiar to democrats at least since ancient Athens. Apart from the selection of trial juries, however, sortition has all but disappeared from official decision-making procedures within contemporary democratic systems, and free, equal, and regular election through voting by the entire qualified population of candidates who put themselves forward for political office, has taken its place. Nevertheless, there has been renewed interest in the idea of reviving sortition-based elements within modern democratic systems over the last years: a number of democratic theorists see great promise in complementing elected decision-making institutions with those selected randomly. These proposals variously go under the names mini-publics, citizen juries, citizen assemblies, lottocracy, enfranchisement lottery, and even Machiavellian Democracy.1 The roots of this practice go back to ancient Athens. During the 5th century Athenian democracy, the equivalent of the parliamentary body tasked with deliberating 1 See for instance, Guerrero 2014; Fishkin 2009; Warren & Gastil 2015; Ryan & Smith 2014; Saunders 2012; López-Guerra 2014; López-Guerra 2011; McCormick 2011. 1 and drafting policy proposals, the boule, was chosen by lot from the citizens of Athens through a complex system of randomization. -
Election by Majority Judgment: Experimental Evidence
Chapter 2 Election by Majority Judgment: Experimental Evidence Michel Balinski and Rida Laraki Introduction Throughout the world, the choice of one from among a set of candidates is accomplished by elections. Elections are mechanisms for amalgamating the wishes of individuals into a decision of society. Many have been proposed and used. Most rely on the idea that voters compare candidates – one is better than another – so have lists of “preferences” in their minds. These include first-past-the-post (in at least two avatars), Condorcet’s method (1785), Borda’s method (1784) (and similar methods that assign scores to places in the lists of preferences and then add them), convolutions of Condorcet’s and/or Borda’s, the single transferable vote (also in at least two versions), and approval voting (in one interpretation). Electoral mechanisms are also used in a host of other circumstances where win- ners and orders-of-finish must be determined by a jury of judges, including figure skaters, divers, gymnasts, pianists, and wines. Invariably, as the great mathemati- cian Laplace (1820) was the first to propose two centuries ago they asked voters (or judges) not to compare but to evaluate the competitors by assigning points from some range, points expressing an absolute measure of the competitors’ mer- its. Laplace suggested the range Œ0; R for some arbitrary positive real number R, whereas practical systems usually fix R at some positive integer. These mechanisms rank the candidates according to the sums or the averages of their points1 (some- times after dropping highest and lowest scores). They have been emulated in various schemes proposed for voting with ranges taken to be integers in Œ0; 100, Œ0; 5, Œ0; 2, or Œ0; 1 (the last approval voting). -
And the Loser Is... Plurality Voting Jean-François Laslier
And the loser is... Plurality Voting Jean-François Laslier To cite this version: Jean-François Laslier. And the loser is... Plurality Voting. 2011. hal-00609810 HAL Id: hal-00609810 https://hal.archives-ouvertes.fr/hal-00609810 Preprint submitted on 20 Jul 2011 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. ECOLE POLYTECHNIQUE CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE AND THE LOSER IS... PLURALITY VOTING Jean-François LASLIER Cahier n° 2011-13 DEPARTEMENT D'ECONOMIE Route de Saclay 91128 PALAISEAU CEDEX (33) 1 69333033 http://www.economie.polytechnique.edu/ mailto:[email protected] And the loser is... Plurality Voting Jean-Franc¸ois Laslier Abstract This paper reports on a vote for choosing the best voting rules that was organized among the participants of the Voting Procedures workshop in July, 2010. Among 18 voting rules, Approval Voting won the contest, and Plurality Voting re- ceived no support at all. 1 Introduction Experts have different opinions as to which is the best voting procedure. The Lever- hulme Trust sponsored 2010 Voting Power in Practice workshop, held at the Chateau du Baffy, Normandy, from 30 July to 2 August 2010, was organized for the purpose of discussing this matter. -
Computational Perspectives on Democracy
Computational Perspectives on Democracy Anson Kahng CMU-CS-21-126 August 2021 Computer Science Department School of Computer Science Carnegie Mellon University Pittsburgh, PA 15213 Thesis Committee: Ariel Procaccia (Chair) Chinmay Kulkarni Nihar Shah Vincent Conitzer (Duke University) David Pennock (Rutgers University) Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy. Copyright c 2021 Anson Kahng This research was sponsored by the National Science Foundation under grant numbers IIS-1350598, CCF- 1525932, and IIS-1714140, the Department of Defense under grant number W911NF1320045, the Office of Naval Research under grant number N000141712428, and the JP Morgan Research grant. The views and conclusions contained in this document are those of the author and should not be interpreted as representing the official policies, either expressed or implied, of any sponsoring institution, the U.S. government or any other entity. Keywords: Computational Social Choice, Theoretical Computer Science, Artificial Intelligence For Grandpa and Harabeoji. iv Abstract Democracy is a natural approach to large-scale decision-making that allows people affected by a potential decision to provide input about the outcome. However, modern implementations of democracy are based on outdated infor- mation technology and must adapt to the changing technological landscape. This thesis explores the relationship between computer science and democracy, which is, crucially, a two-way street—just as principles from computer science can be used to analyze and design democratic paradigms, ideas from democracy can be used to solve hard problems in computer science. Question 1: What can computer science do for democracy? To explore this first question, we examine the theoretical foundations of three democratic paradigms: liquid democracy, participatory budgeting, and multiwinner elections.